Surgical Pathology Case Study: A 2.5 Year Old Male Who Presents with Jaundice and Pruritus

Case History

The patient is a 2.5 year old male who is being evaluated for a liver transplant versus biliary diversion surgery. The patient was born at 2 kilograms and went home with mom one week after birth. The patient was readmitted back to the hospital for evaluation of jaundice and since then the patient has been intermittently hospitalized for episodes of worsening jaundice, acholic stools, scleral icterus, and pruritus. At 5 months of age, the patient was diagnosed with progressive familial intrahepatic cholestasis, type 2, and was placed on the liver transplant list. As a result of the liver failure, the patient has developed coagulopathy, hypocalcemia resulting in seizures, and pruritus. The family history is significant for no known congenital liver diseases.

Table 1. Pertinent lab findings.

The father was worked up for living donation and was found to be a suitable donor, and is donating the left lateral segment of his liver.

Diagnosis

Received in the Surgical Pathology laboratory is a 700 gm, 23.5 x 14.5 x 3.5 cm explanted liver with an attached 4.5 x 1.2 x 0.4 cm gallbladder. The liver specimen has a smooth, green-red liver capsule without any grossly identifiable nodules or lesions (Image 1). The gallbladder has a yellow-pink external surface and is opened to reveal a 1.5 x 0.7 x 0.4 cm dark brown stone with a small amount of brown-yellow bile fluid. The liver is sectioned to reveal a smooth green-red cut surface (Image 2). No lesions are identified and minimal hilar structures are included with the specimen. Portions of the specimen have been taken for electron microscopy and frozen for future diagnostic purposes. Submitted sections include:

Cassette 1 and 2:   Hilar structures

Cassettes 3-15:   Representative sections of liver parenchyma

Cassette 16:   representative section of gallbladder

Image 1. Posterior aspect of green-tinged liver
Image 2. Cut section of liver

On microscopy, the trichrome stain highlights the presence of portal and centrilobular fibrosis, with focal bridging. However, regenerative nodule formation is not evident. The portal tracts contain sparse mononuclear cell infiltrates. Significant bile ductular proliferation is also evident, as confirmed by a CK7 immunostain. However, the native bile ducts appear unremarkable. There is also considerable hepatocellular and canalicular cholestasis in the centrilobular regions. Occasional multinucleated hepatocytes are also seen within the centrolobular zones. No steatosis is evident.

This constellation of histologic features is consistent with the clinical history of progressive familial intrahepatic cholestasis, type II.

Discussion

Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive disorders that affects bile formation and results in cholestasis of the liver, usually beginning in infancy and childhood. There are three types of PFIC, each related to a mutation in the liver transport system genes that are involved in bile formation. PFIC type 1 (PFIC1), which is also referred to as Byler disease, is due to impaired bile salt secretion related to a ATP8B1 gene that encodes the FIC1 protein. PFIC type 2 (PFIC2), which is referred to as Byler syndrome, is due to impaired bile salt secretion (similar to type 1), but is related to the ABCB11 gene that encodes the bile salt export pump, or BSEP. PFIC type 3 (PFIC3) is due to impaired biliary phospholipid secretion that is related to a defect in the ABCB4 gene that encodes the multi-drug resistant 3 protein, or MDR3.

PFIC is suspected to be the cause of cholestasis in 10-15% of children, and is also the underlying cause of liver transplants in 10-15% of children. The exact prevalence remains unknown, but is estimated to be between 1 in every 50,000-100,000 births. PFIC1 and PFIC2 account for 2/3 of all PFIC cases, with PFIC3 making up the other 1/3. PFIC is present worldwide, and there does not appear to be a gender predilection.

The main clinical manifestation in all forms of PFIC, hence the name, is cholestasis, and will usually appear in the first few months of life with PFIC1 and PFIC2. Recurring episodes of jaundice are also present in PFIC1, whereas permanent jaundice and a rapid evolution to liver failure are characteristic of PFIC2. In PFIC3, cholestasis is noted within the first year of life in 1/3 of all cases, but rarely will be present in the neonatal period. PFIC3 can also present later in infancy, childhood or even early adulthood, with gastrointestinal bleeding due to portal hypertension and cirrhosis being the main symptoms that the patient would present with. Pruritus is severe in PFIC 1 and 2, but has a more mild presentation in PFIC3. There have been multiple cases reported of hepatocellular carcinoma that are associated with PFIC2, but there so far have not been any cases of hepatocellular carcinoma reported that are associated with PFIC3. Other signs and symptoms that may be present in PFIC1 include short stature, deafness, diarrhea, pancreatitis and liver steatosis. When examining clinical laboratory results, patients with PFIC1 and PFIC 2 will have normal serum gamma-glutamyltransferase (GGT) levels, but patients with PFIC3 will have elevated GGT levels. PFIC1 and PFIC2 can be differentiated from each other by the higher transaminase and alpha-fetoprotein levels that are found in PFIC2. When analyzing the biliary bile salt concentrations, PFIC1 will have mildly decreased levels (3-8 mM), PFIC2 will have drastically decreased levels (<1 mM), and PFIC3 will have normal levels. In addition, the biliary bile salt:phospholipid ratio and the cholesterol:phospholipid ratio will be approximately 5 times higher in PFIC3 than in normal bile, due to the biliary phospholipid levels being dramatically decreased (normal phospholipid range = 19-24%, PFIC phospholipid range = 1-15%).

Histologically, PFIC1 and PFIC 2 will have canalicular cholestasis, an absence of true ductular proliferation, and periportal biliary metaplasia of the hepatocytes. In PFIC2, these manifestations are much more worrisome with more marked lobular and portal fibrosis, and inflammation, as well as having much more pronounced necrosis and giant cell transformation (Images 3 and 4). PFIC3 will show portal fibrosis and true ductal proliferation, with a mixed inflammatory infiltrate. In addition, cholestasis can be present in the lobule and in some of the ductules that contain bile plugs. Cytokeratin staining can help confirm the ductular proliferation within the portal tract. Mild or absent canalicular staining with BSEP and MDR3 antibodies will help to diagnose PFIC2 and PFIC3, respectively.

Image 3. Photomicrograph demonstrating cholestasis, centrilobular necrosis, lobular inflammation, and giant cells (H&E)
Image 4. Photomicrograph demonstrating portal, centrilobular and bridging fibrosis (Trichrome)

A diagnosis of PFIC is based on the clinical manifestations, liver ultrasonography, cholangiography and liver histology, as well as on specific tests for excluding other causes of childhood cholestasis (such as biliary atresia, Alagille syndrome, cystic fibrosis and alpha-1 antitrypsine deficiency). Ultrasonography of the liver will be normal with the exception of a possible dilated gallbladder. At the time of the liver biopsy, a portion of tissue can be submitted for electron microscopy, which in the case of PFIC, can show canalicular dilatation, microvilli loss, abnormal mitochondrial internal structures, and varying intra-canalicular accumulations of bile. PFIC1 will have coarsely, granular bile on electron microscopy, whereas PFIC2 will have a more amorphous appearance. If biliary obstruction is noted on the liver biopsy, a cholangiography will need to be performed to exclude sclerosing cholangitis. If a normal biliary tree is observed, as in PFIC, bile can be collected for biliary bile salt analysis (which was discussed earlier in the laboratory results section). Differentiating between PFIC1, PFIC2 and PFIC3 can be quite troublesome, but luckily Davit-Spraul, Gonzales, Baussan and Jacquemin proposed a fantastic schematic for the clinical diagnosis of PFIC, which is presented as Figure 1.

Figure 1. Schematic proposed for the clinical diagnosis of progressive familial intrahepatic cholestasis

Ursodeoxycholic acid (UDCA) therapy should be considered in all patients with PFIC to prevent liver damage and provide relief from pruritus. Rifampicin and Cholestyramine can help in cases of PFIC3, but have been found to provide no improvement in PFIC1 or PFIC2. In some PFIC1 or PFIC2 patients, biliary diversion can also relieve pruritus and slow disease progression. The total caloric intake should be around 125% of the recommended daily allowance. Dietary fats should come in the form of medium chain triglycerides, and care should be taken to check the patient’s vitamin levels to look for signs of vitamin deficiency. Patients with PFIC2 should be monitored for hepatocellular carcinoma, beginning from the first year of life. Ultimately, most PFIC patients develop fibrosis and end-stage liver disease before adulthood, and are candidates for liver transplantation. Diarrhea, steatosis and short stature may not improve after liver transplantation, and could become aggravated from the procedure. Hepatocyte transplantation, gene therapy or specific targeted pharmacotherapy are possible alternative therapies for PFIC, but will require more research and studies to determine whether they are viable options.

References

  1. Davit-Spraul A, Gonzales E, Baussan C, Jacquemin E. Progressive familial intrahepatic cholestasis. Orphanet J Rare Dis. 2009;4(1). doi:10.1186/1750-1172-4-1
  2. Evason K, Bove KE, Finegold MJ, et al. Morphologic findings in progressive familial intrahepatic cholestasis 2 (PFIC2): correlation with genetic and immunohistochemical studies. Am J Surg Pathol. 2011;35(5):687–696. doi:10.1097/PAS.0b013e318212ec87
  3. Srivastava A. Progressive Familial Intrahepatic Cholestasis. J Clin Exp Hepatol. 2013;4(1):25-36. doi: 10.1016/j.jceh.2013.10.005

-Cory Nash is a board certified Pathologists’ Assistant, specializing in surgical and gross pathology. He currently works as a Pathologists’ Assistant at the University of Chicago Medical Center. His job involves the macroscopic examination, dissection and tissue submission of surgical specimens, ranging from biopsies to multi-organ resections. Cory has a special interest in head and neck pathology, as well as bone and soft tissue pathology. Cory can be followed on twitter at @iplaywithorgans.

Surgical Pathology Case Study: A 63 Year Old Male with a ~60 Year Recurring Neck Mass

Case History

A 63 year old man presented with a long standing history of a recurring pleomorphic adenoma of the parotid gland. As a child, the patient had radiotherapy to the bilateral parotid glands for parotid swelling. He then developed a left parotid mass ~15 years later and underwent parotidectomy. After another recurrence ~15 years after the initial parotidectomy, he underwent a second resection of multiple masses in the preauricular region. The patient then developed a recurrence ~20 years after the second resection and underwent neutron beam therapy. The patient tolerated the treatment well noting mild dry mouth, which is persistent, and left ear pain, but otherwise has no major long-term sequelae from the treatment. Eighteen years after the neutron beam therapy, the patient developed a left submandibular mass. A subsequent biopsy of the mass revealed a pleomorphic adenoma.  Enlarged left and right submental and submandibular nodes were noted, with biopsies performed at an outside hospital of these nodes demonstrating metastatic poorly differentiated carcinoma within three lymph nodes. It was noted on this pathology report that the histological features, in light of the history, could represent a carcinoma ex pleomorphic adenoma. A CT scan of the head and neck revealed a large multiloculated, cystic, rim-enhancing mass within the left parotid gland, as well as large enhancing lymph nodes within the right anterior and posterior cervical triangle and the right submandibular space, the largest of which measured 2.1 cm. A PET scan showed increased activity within the right neck. Upon meeting with otolaryngology, a 4.0 x 7.0 cm lobular, non-fixed left parotid mass, and two level 1B right sided nodes, were palpated. Based on the patient’s history, physical exam, and prior biopsy results, it was decided to proceed with a parotidectomy and bilateral neck dissection. 

Diagnosis

Received in the Surgical Pathology laboratory is a soft tissue mass resection from the area of the left parotid gland measuring 9.0 x 6.0 x 4.2 cm. The specimen is oriented by a single long stitch designating the superior aspect, and a double long stitch designating the lateral aspect (Figure 1). The specimen is entirely inked black, and then bisected to reveal multiple discrete, white-tan, partially cystic masses ranging in size from 0.2-4.0 cm in greatest dimension and measuring 7.0 x 3.5 x 3.0 cm in aggregate dimension (Figure 2). The largest mass is partially cystic with the cystic component measuring 1.2 cm in greatest dimension. This largest mass abuts the anterior, medial and lateral margins. The remaining tumor deposits are located:

– 1.2 cm from the inferior margin

– 0.4 cm from the superior margin

– 0.9 cm from the posterior margin

No gross salivary gland tissue is identified. The remainder of the specimen consists of unremarkable yellow adipose tissue and red-brown skeletal muscle. The specimen is submitted as follows.

Cassette 1:   superior margin

Cassette 2:   representative sections of anterior margin

Cassette 3:   anterior superior margin

Cassette 4:   anterior inferior margin

Cassette 5:   posterior margin

Cassette 6-9:   representative sections of mass with approach to lateral margin

Cassette 10:   representative sections of mass with approach to medial margin

Cassette 11:   mass in relation to surrounding skeletal muscle

Cassette12-15:   representative sections of mass

On microscopy, the specimen contains nests of tumor cells ranging in size from 0.2 to 4.0 cm within a dense fibrous matrix. Although these deposits may represent lymph node metastases, no residual lymphoid tissue is present. The tumor is represented by residual pleomorphic adenoma and numerous soft tissue deposits of pleomorphic adenoma (Figure 3). Admixed are broad areas of high grade carcinoma with necrosis (Figure 4). Most regions show adenocarcinoma, although a rare focus of squamous differentiation is also present. The lateral margin is positive for carcinoma, and a pleomorphic adenoma component approaches within 0.1 cm of the medial margin. The anterior, posterior, inferior, and superior margins are all free of tumor. No salivary gland tissue is identified.

In addition, eleven frozen sections are submitted from various areas surrounding the mass, with five of the eleven frozen sections demonstrating tumor deposits. A right neck dissection is performed with following results:

Level IB: 2 of 3 positive (largest deposit: 1.8 cm)

Level II and III: 1 of 14 positive, Level II (1.9cm)

Level IV: 1 of 8 positive (2.0 cm)

Based on these results, the specimen was signed out as carcinoma ex-pleomorphic adenoma, and designated as pT4aN2cMx

Figure 3. 2x photomicrograph showing a classic appearing pleomorphic adenoma with satellite nodules along the periphery

Discussion

Carcinoma ex pleomorphic adenoma (CXPA) is a carcinoma that arises in a primary (de novo) or recurrent benign pleomorphic adenoma (PA). While a PA is the most common salivary gland tumor, accounting for approximately 80% of all benign salivary gland tumors, a CXPA is quite uncommon, accounting for only 3.6% of all salivary gland tumors. CXPA is predominantly found in the sixth to eighth decades of life, with a slight predilection for females. CXPA arises most commonly in the salivary glands, in particular the parotid and the submandibular glands. CXPA can also arise in the minor salivary glands in the oral cavity, although these tumors tend to be smaller than their counterparts in the parotid and submandibular gland. There have also been cases of CXPA in the breast, lacrimal gland, trachea, and nasal cavity.

Clinically, CXPA presents as a firm, asymptomatic mass that can go undetected for years since they are not generally invasive. When the patient does experience any symptoms, with pain being the most common, it is usually due to the mass extending to adjacent structures. If the mass was to involve the facial nerve, paresis or palsy can occur. Other signs and symptoms include skin ulceration, mass enlargement, skin fixation, lymphadenopathy, dental pain, and dysphagia. The onset of symptoms can range anywhere from 1 month up to 60 years (such as with this case), with a mean onset of 9 years. Half of patients will have a painless mass for less than 1 year. Since these symptoms are similar to those of a benign PA, it’s important that the treating physician be aware of the possibility of a CXPA, especially considering the rarity of the cancer.

Grossly, CXPA appears as a firm, ill-defined tumor, and can vary greatly depending on the predominant component. If the PA is the predominant component, the mass may appear gray-blue and translucent, and it could be possible to grossly differentiate between the PA areas and the CXPA areas. If the malignant component predominates, then the mass may contain cystic, hemorrhagic and necrotic areas.

Microscopically, CXPA is defined as having a mixture of a benign PA, admixed with carcinomatous components. Zbaren et al, in an analysis of 19 CXPA cases, found 21% of the tumors were composed of less than 33% carcinoma, 37% of the tumors were composed of 33-66% carcinoma, and 42% of the tumors were composed of greater than 66% carcinoma. Most often, the malignant component is adenocarcinoma, but can also include adenoid cystic carcinoma, mucoepidermoid carcinoma, salivary duct carcinoma, and other less common variations. In cases where the entire tumor is replaced by carcinoma, the diagnosis of CXPA will be based on the presence of a PA on the previous biopsy. Conversely, you could also have a tumor that is predominately composed of a PA, with sparse areas of malignant transformation, such as nuclear pleomorphism, atypical mitotic figures, hemorrhage and necrosis. The likelihood of malignant transformation increases with the length of the PA being present, from 1.5% at 5 years, up to 10% after 15 years.

CXPA can be further sub-divided into four categories based on the extent of invasion of the carcinomatous component outside the capsule: in-situ, non-invasive, minimally invasive, and invasive carcinoma.

#1) In-situ carcinoma occurs when nuclear pleomorphism and atypical mitotic figures are found within the epithelial cells, but do not extend out beyond the border of the myoepithelial cells (Figure 5).

#2) Non-invasive CXPA, which can include in-situ carcinoma, is maintained within the fibrous capsule of the PA, but extends beyond the confines of the myoepithelial cells. Non-invasive CXPA may begin to show malignant transformation, but will overall behave like a benign PA.

#3) Minimally invasive CXPA is defined as <1.5 mm extension into the extracapsular tissue, with a mix of benign PA components and carcinomatous components.

#4) Invasive CXPA is defined as a > 1.5 mm extension into the extracapsular tissue, and will begin to demonstrate more carcinomatous components, such as hemorrhage and necrosis.

As the carcinomatous areas begin to increase in prevalence, the PA nodules will begin to be composed of hyalinized tissue with sparse, scattered ductal structures, and the malignant cells will begin to decrease in size as they move away from the site of origin. Perineural and vascular invasion can be easily identified as the tumor extends into the neighboring tissue (Figure 6).

The development of CXPA has been shown to follow a multi-step model of carcinogenesis with a loss of heterozygosity at chromosomal arms 8q, followed by 12q, and finally 17p. Both PA and CXPA demonstrate the same loss of heterozygosity, however, the carcinomatous components exhibit a slightly higher loss of heterozygosity at 8q, and a significantly higher loss of heterozygosity at 12q and 17q. The early alterations of the chromosomal arm 8q in a PA often involves PLAG1 and MYC, with the malignant transformation of the PA to a CXPA being associated with the 12q genes HMGA2 and MDM2.

Treatment for CXPA involves surgery, radiotherapy and chemotherapy, with a parotidectomy being the most common procedure performed. If a benign PA had originally been resected, but residual remnants of the PA were left behind, then satellite PA nodules will arise in its place (Figure 3). If in-situ, non-invasive or minimally invasive carcinoma is suspected in the superficial lobe of the parotid gland, than a superficial parotidectomy can be performed. Invasive carcinoma will result in a total parotidectomy, with every attempt made to try and preserve the facial nerve. If metastasis is suspected to the cervical lymph nodes, a neck dissection may also be performed. Reconstructive surgery following the removal of the tumor may be necessary, depending on where the tumor was resected from. Other treatment options currently being considered include a combination therapy of trastuzumab and capecitabine, as well as the possibility of a WT1 peptide based immunotherapy.

Figure 5. 40x microphotograph demonstrating an in-situ carcinoma confined within the myoepithelial cells
Figure 6. 10x photomicrograph of carcinoma at the lateral margin with areas of perineural invasion

References

  1. Antony J, Gopalan V, Smith RA, Lam AK. Carcinoma ex pleomorphic adenoma: a comprehensive review of clinical, pathological and molecular data. Head Neck Pathol. 2011;6(1):1–9. doi:10.1007/s12105-011-0281-z
  2. Chooback N, Shen Y, Jones M, et al. Carcinoma ex pleomorphic adenoma: case report and options for systemic therapy. Curr Oncol. 2017;24(3):e251–e254. doi:10.3747/co.24.3588
  3. Di Palma S. Carcinoma ex pleomorphic adenoma, with particular emphasis on early lesions. Head Neck Pathol. 2013;7 Suppl 1(Suppl 1):S68–S76. doi:10.1007/s12105-013-0454-z
  4. Handra-Luca A. Malignant mixed tumor. Pathology Outlines. http://www.pathologyoutlines.com/topic/salivaryglandsmalignantmixedtumor.html. Revised March 21, 2019. Accessed April 5, 2019.

-Cory Nash is a board certified Pathologists’ Assistant, specializing in surgical and gross pathology. He currently works as a Pathologists’ Assistant at the University of Chicago Medical Center. His job involves the macroscopic examination, dissection and tissue submission of surgical specimens, ranging from biopsies to multi-organ resections. Cory has a special interest in head and neck pathology, as well as bone and soft tissue pathology. Cory can be followed on twitter at @iplaywithorgans.

Gastric Cancer: A Multidisciplinary Approach

Maryam Zenali1*, Dmitriy Akselrod2, Eric Ganguly3, Eswar Tipirneni4 and Christopher J. Anker5*

1 Department of Pathology, 2 Department of Radiology, 3 Division of Gastroenterology, and 5 Division of Radiation Oncology, The University of Vermont Medical Center (UVMMC), Burlington, VT and 4 Department of Hematology Oncology, Central Vermont Medical Center (CVMC), The University Of Vermont Health Network, Adult Primary Care, Berlin, VT

*corresponding authors

A 57 year old woman with a personal and family history of breast cancer presented with early satiety and dysphagia for 5 months. Her abdominal computed tomography (CT) scan (Image 1 A) showed marked thickening of an apparently featureless gastric wall (A, blue arrows indicating the mucosal [rightward pointing] and serosal [leftward pointing] aspects of the gastric wall). Prominent gastrohepatic lymph nodes were noted as well. Her fluoroscopic upper GI study (Image1 B), following administration of barium and effervescent crystals (a double contrast effect to allow for mucosal evaluation), showed thickened rugal folds (B red arrow) and pooling of barium within an antral ulcer (B blue arrow). A subsequent CT scan (Image 1 C) after administration of intravenous and enteric contrast, confirmed marked diffuse gastric wall thickening (C blue arrows again indicating the mucosal [rightward pointing] and serosal [leftward pointing] aspects of the gastric wall) (Image 1, composite radiographs A-C).

The gastric body distended poorly with insufflation and demonstrated thickened, erythematous, edematous folds with erosions (Image 2, endoscopy image). On endoscopic ultrasound, the total thickness of the stomach was 12 mm with expanded wall layers in the proximal stomach to the antrum and a thickness of 3.5 mm in spared areas. Biopsies were obtained; the corresponding H&E and keratin stains are provided (Image 3, composite photomicrographs A-B).

Image 1. Composite radiographs.
Image 2. Endoscopy image.
Image 3. Composite photomicrographs.

Based on the original radiographic imaging that led to the biopsy, what are the differential diagnoses?

Surgical Pathology Case Study: A 42 Year Old Woman with an Enlarging Mass of the Forearm

Case History

A 42 year old female with a history of neurofibromatosis, hypertension and Hashimoto’s thyroiditis had noted a mass on her forearm approximately 15 years ago. According to the patient, the mass did not change in size and did not cause her any discomfort during that time. Approximately 6 months prior to presenting to her primary physician, the mass began to increase in size and caused discomfort and pain. Upon examination with the Orthopedic Surgery department, a 20 x 20 cm firm, smooth mass on her forearm with mild pain on palpation was noted (Image 1). On MRI, the mass appeared to partially surround the radius and ulna, and encased the median, radial and ulnar nerves. A needle core biopsy was subsequently performed on the mass revealing a high grade malignant peripheral nerve sheath tumor (MPNST). A CT scan of the chest showed no evidence of metastatic disease. During her clinical visit, the use of neoadjuvant chemotherapy and chemoradiotherapy were discussed, but based on the large size of the mass, tumor response would have to be significant in order to allow for limb conserving surgery. At the time that the patient was seen, MPNSTs were not known to be chemosensitive and the chances of significant tumor response was very low (clinical drug trials have since shown some improvements in this area). In light of the poor response to systemic therapy of these tumors and the potentially toxic side effects of chemotherapy, the decision was made to proceed with amputation of the arm through the humerus.

Diagnosis

Frozen sections were sent from all the major peripheral nerves, including the ulnar, radial and median nerves. There was no evidence of any tumor consistent with a high-grade MPNST, although there was evidence of neurofibromas. There were atypical cells with hyperchromasia in the ulnar nerve margin, however, this was not considered to be consistent with a high grade MPNST. Received in the surgical pathology lab was an above elbow amputation consisting of a 30.0 cm long distal arm, an attached hand measuring 17.0 cm in maximum length., and a 4.5 cm long exposed humerus. The specimen is covered by grossly unremarkable skin, with a palpable mass in the mid-portion of the forearm. Sectioning reveals an 18.0 x 12.0 x 11.0 cm well-circumscribed mass composed of bulging, myxoid, white-tan tissue with central areas of hemorrhagic degeneration and yellow-tan friable tissue (Image 2). The bulging white-tan tissue is mainly found peripherally and encompasses approximately two-thirds of the mass. The mass is confined to a thin translucent lining and does not grossly invade neighboring soft tissue or overlying skin. The radial, median and ulnar nerves are adjacent to but not invaded by the mass, although the distal aspect of the mass shares a translucent, myxoid-like tissue with the peripheral nerve sheath of the ulnar and median nerves.

In addition to the standard bone and soft tissue margins that are taken, representative sections of the mass with the closest approach to the overlying skin are submitted. Sections demonstrating the relationship of the distal mass to the radial, median and ulnar nerves are submitted in separate cassettes. Lastly, representative sections sampled from various areas of the mass are submitted in an additional 15 blocks.

Histologically, the tumor consisted of spindle cells arranged in a fascicular pattern with intermittent whorled areas. The cells contained pleomorphic, hyperchromatic nuclei and intervening myxoid hypocellular areas. Mitotic figures were observed with sparse areas of necrosis and hemorrhage. S-100 was ordered on the prior biopsy of the mass, which was weakly positive. Based on these findings, the specimen was signed out as a malignant peripheral nerve sheath tumor.

Image 1. Above elbow amputation with a large forearm mass.
Image 2. Longitudinal cross section of arm demonstrating a bulging, white-tan mass with areas of hemorrhage and necrosis.

Discussion

Malignant peripheral nerve sheath tumors (MPNST) are locally invasive tumors that are associated with medium to large nerves (as opposed to cranial or distal small verves) and commonly recur with eventual metastatic spread. Common sites for metastatic spread include lung, liver, brain, bones and adrenals. They are usually found in adults between the second and fifth decades of life, and account for only 5% of malignant soft tissue tumors. Approximately half of MPNSTs will occur sporadically, with the other half generally arising in the setting of neurofibromatosis type 1 (such as in this case). There is a high clinical suspicion for MPNST if the patient has a history of neurofibromatosis type 1 or if the tumor arises within a major nerve component.

Grossly, MPNST will present as a large, poorly defined, fleshy tumor that runs along a nerve and involves adjacent soft tissue. Often, these tumors will have areas of hemorrhage or necrosis and can track along the length of a nerve. Histologically, the tumors are composed of monomorphic spindle cells arranged in fascicles, palisades and whorls, with compact comma-shaped, wavy or buckled hyperchromatic nuclei with alternating hypocellular foci. (Image 3 and 4). Mitotic figures and necrosis are common, and although S-100 is considered the best marker for MPNST, there is a lack of specificity and sensitivity for immunohistochemical markers. Due to the lack of immunohistochemical markers and molecular findings, as well as the variability associated with the cells, it has traditionally been difficult to diagnose MPNST. The differential diagnosis includes fibrosarcoma, monophasic synovial sarcoma, desmoplastic melanoma, and pleomorphic liposarcoma. Goldblum et al put forth the idea that a diagnosis of MPNST can be made if the tumor falls into any one of the following three categories:

  1. The tumor arises along a peripheral nerve
  2. The tumor arises from a pre-existing benign nerve sheath tumor, such as a neurofibroma
  3. The histologic features are consistent with a malignant Schwann cell tumor

Unfortunately, due to the aggressiveness of the tumor and high recurrence rate, MPNST has a poor prognosis with a 2 year overall survival rate of around 57% and a 5 year survival rate around 39%.

Image 3. Low power photomicrograph showing a spindle cell neoplasm arranged in a fascicular pattern.
Image 4. High power photomicrograph demonstrating spindle cells with hypercellular nuclei in a whorled arrangement and adjacent myxoid hypocellular areas.

References

  1. Case of the week #443. Pathology Outlines. http://www.pathologyoutlines.com/caseofweek/case443.htm. Published November 15, 2017. Accessed March 10, 2019.
  2. Frosch MP, Anthony DC, De Girolami U. Malignant Peripheral Nerve Sheath Tumor. In: Kumar V, Abbas AK, Fausto N, Aster JC. Robbins and Cotran Pathologic Basis of Disease, 8th edition. Philadelphia, PA: Elsevier, Inc. 2010: 1341-1342
  3. Guo A, Liu A, Wei L, Song X. Malignant Peripheral Nerve Sheath Tumors: Differentiation Patterns and Immunohistochemical Features – A Mini-Review and Our New Findings. J Cancer. 2012; 3:303-309. http://www.jcancer.org/v03p0303.html. Accessed March 9, 2019.
  4. Hirbe AC, Cosper PF, Dahiya S, Van Tine BA. Neoadjuvant Ifosfamide and Epirubicin in the Treatment of Malignant Peripheral Nerve Sheath Tumors. Sarcoma. https://www.hindawi.com/journals/sarcoma/2017/3761292/cta/. Accessed March 10, 2019.
  5. Ramnani, DM. Malignant Peripheral Nerve Sheath Tumor. WebPathology. https://www.webpathology.com/case.asp?case=499. Accessed March 9, 2019.
  6. Shankar V. Malignant peripheral nerve sheath tumor (MPNST). Pathology Outlines. http://www.pathologyoutlines.com/topic/softtissuempnst.html. Revised September 12, 2018. Accessed March 9, 2019.

-Cory Nash is a board certified Pathologists’ Assistant, specializing in surgical and gross pathology. He currently works as a Pathologists’ Assistant at the University of Chicago Medical Center. His job involves the macroscopic examination, dissection and tissue submission of surgical specimens, ranging from biopsies to multi-organ resections. Cory has a special interest in head and neck pathology, as well as bone and soft tissue pathology. Cory can be followed on twitter at @iplaywithorgans.

Just Say Know! From Mentoring to High Performance: A Resident Perspective

As pathologists, we are responsible for increasingly intricate anatomic pathology and clinical laboratory services in a continually changing healthcare landscape that requires us to integrate emerging technologies for improved quality of medical care while also being hypervigilant to cost control and efficiency. Hospital systems working under managed care business models seek to expand their coverage networks and boost the number of patients served, and as such, it is going to be very critical for the next generation of pathologists to develop and implement the management skills and techniques necessary to effectively advocate for investment in their departments and meet such goals.

The problem, however, is that we are largely shielded from these issues during our undergraduate and even graduate medical education experiences. We focus, of course, on the basic sciences and clinical skills, which are undeniably important; however, we get significantly less instruction or discussion on functioning within our health care system, addressing quality issues, or general leadership training that is indispensable and highly valuable for practicing physicians.

Earlier in the summer, I saw a number of pathology folks on Twitter promoting and strongly encouraging residents to apply for the two-day “Just Say Know! From Mentoring to High Performance” program, formed through collaboration between ASCP and USCAP, on an approach to leadership, management, and business for pathology. I was highly intrigued and had a feeling this program was the sort of experience for which I had been looking. Traveling to Palm Springs in the middle of the Chicago winter was not a bad deal either!

Drs. Blair Holladay and David Kaminsky assembled an impressive collection of speakers for the weekend, which was divided into four focus areas: leadership, management, business and policy, and change. After an engaging introduction by Drs. Holladay and Kaminsky, current trainees Drs. Kabeer Shah and Melissa Hogan set the stage by highlighting the increasing importance of “management” and “leadership” as reflected in the ACGME milestones as well as recent literature suggesting expectations for newly-trained pathologists include these very skills (Post et al. Arch Pathol Lab Med 2017;141: 193-202).Above all, they encouraged all of the thirty residents and fellows in attendance to “be honest, be open, and be vulnerable,” and ask the tough questions of themselves to gain the most from the weekend.

Lotte Mulder from ASCP led an enlightening discussion on the differences between emotional intelligence (EI) and conventional IQ, as well as the critical need to be self-aware of how our emotions can affect our performance and to understand the extent of our own abilities, strengths, and weaknesses. Dr. Karen Kaul followed with a very timely overview of strategies for identifying mentors. She discussed how our mentorship needs will evolve over the course of our careers and that fulfilling the mentor role for another junior individual while having your own mentors is key to the professional development necessary in leadership positions.

 After lunch, Dr. Dan Milner from ASCP took us through some very interesting global health case studies that forced our group to think critically about the role of pathology and the clinical laboratory in underserved settings as well as the major obstacles and economic disparities that must be considered. There were a number of important teaching points from Dr. Milner’s international cases that will be equally helpful for understanding the disparities we encounter right here in our backyard.

Dr .Yael Heher led off the afternoon management focus series with a really comprehensive look into how she has championed quality improvement and patient safety reviews at her institution to address root causes for laboratory errors, followed by a well-timed interactive session in which we divided into groups to use the six sigma methodology to work in concrete steps through a real-life laboratory error. It was a great opportunity to see people from different institutions and backgrounds bring unique perspectives to a common problem. The first day of the program concluded with a very unique session on art and leadership in which Dr. Kaminsky led us into Downtown Palm Springs to view the Palm Springs Babies art installation set up by David Cerny. Our powers of observation as pathologists were put to the test as we were asked to describe and interpret the meanings behind the exhibit in the same way that we often use visual evidence in our day-to-day work.

The second day of the program focused on business and policy with talks by Dr. Gary Procop on how pathologists can help integrate interventions into the laboratory to improve system-level metrics and by Khosrow Shotorbani on how laboratory data can be used to optimize laboratory services in the model of the rideshare service, Uber. The morning also included an interactive session on negotiation skills, in which each of us assumed the roles of departmental chair and owner of a private practice group negotiating with newly-hired pathologists. The weekend concluded with Dr. Nathan Johnson’s 18 steps to make change a part of an organizational culture, which was based on his experiences in academic research, military operational theory, and real-life lab experiences.

The weekend provided an incredibly impactful and high-yield array of discussions, so much so that I am already finding myself applying many of the strategies and techniques described over the weekend in my role as chief resident as well as to some of the changes and initiatives that I am hoping to bring to our department. Most important, though, were the opportunities to interact with my peers from around the country. We all face similar challenges as residents, and the opportunity to learn each other’s perspectives and approaches to similar issues was just as illuminating as the structured portions of the program. I hope that the ASCP and USCAP continue to offer the Just Say Know! Program and enthusiastically join all those pathology folks on social media promoting the program last summer with my own strong recommendation to challenge yourself and be open to new ways of learning by considering participating in this event!

From Twitter, @Blair_Holladay, December 12, 2018
Photo by Imran Uraizee

-Imran Uraizee, MD, is currently chief resident and a third-year anatomic and clinical pathology resident at the University of Chicago. He also manages the Department of Pathology Twitter account, @UChicagoPath. He majored in Biology at Duke University before earning his MD at the University of Rochester School of Medicine and Dentistry. Dr. Uraizee can be followed on Twitter at @IUraizee3MD.

Dead Wrong About Forensic Pathology

(•_•)         ( •_•)>⌐■-■       (⌐■_■)

[Puts my sunglasses on dramatically]

[Won’t Get Fooled Again by The Who plays]

Image 1. Looks like this medical lab science blogger made quite the … shady… joke. CSI: Miami’s Lt. Horatio Caine (played by David Caruso) donned his shades at pivotal plot times. (Source: CBS)

Okay-okay, I couldn’t resist that. How many times have you just wanted a CSI-style joke on here? No? Just me? That’s fine…

Hello again everybody! Welcome back! Last month I talked a bit about “Just Culture,” a sort of bridge between the values we tout as clinical leaders in our laboratories and the medical culture’s evolving and value-informed paradigm shift. There was a little in there about the lessons paralleled in LMU and the benefits of interdisciplinary teamwork. This month, on the subject of interdisciplinary collaboration, I’d like to talk about our colleagues who often are secluded or in more remote areas in our hospitals, offices, and academic centers. Not here to stereotype; I’m talking about our friends in forensic pathology!

Before I get there, let me go back a bit. I’ve already written several times about the stereotypes that surround our field of lab medicine and there are two times when that is glaringly present: when you’re a medical student or when you’re in forensics. I got the chance to meet someone who falls into both categories.

I’ve just finished up my OB/GYN rotation. But before my last day, I went to the lab at our hospital and followed up on some pending biopsy results. Okay, I can’t lie to you guys: they wanted me to see if I could rush “my lab friends” to expedite the process of fixing, setting, cutting, staining, and reading/reporting—because that’s possible. So, I went to the lab and had a pleasant chat with the staff explaining the situation and they were happy to help. While I was there, however, I happened to see another short white coat (ironically from my same school) who was helping some lab personnel with some grossing. Turns out she wants to match into a pathology residency—just like me—and specifically was interested in forensic path, a field which I don’t know much about. After talking more, I asked if she’d like to share some information. Here’s my conversation with Kyla Jorgenson, a 3rd year medical student at AUC-SOM from Toronto, Canada:

I get lots of hassle when I say I want to become a pathologist. People often ask me, “what’s your back up choice” or “don’t you like patients?” It can be a challenge. What’s your experience been like?

You want to do autopsies, so you want to be a mortician, right? Not quite. Many times, I’ve been faced with blank stares when I say I want to be a forensic pathologist. Other times I get the other end of the spectrum, that’s so cool! Clearly, they’ve seen a few crime-shows and think that I’ll get to go to crime scenes in stiletto high heeled shoes with a song by The Who playing in the background as I arrive. Even today when talking with a dermatopathologist I got a, “well when you realize that hanging out with dead bodies every day isn’t the greatest, you might consider surg path.” Then after hearing my experience as an autopsy assistant and that I’m sure this is what I want to do it was the resigned sigh signalling that I was a lost cause already.

A “lost cause,” that’s frustrating. A lot of specialities rag on other ones, it seems to be part of the culture of medicine—hopefully not forever, but still can’t we all just get along?

So, my background leading to pathology involved me working for several years between college, graduate school, and medical school; in hospitals of various sizes. I have personal experiences in these fields and sort of feel “at home” when I’m dealing with hematopathology, transfusion medicine, cell therapy—that sort of thing. What piqued your interest in forensics?

I started my undergraduate degree in forensic biology at the University of Toronto in the fall of 2008 just as a major review of pediatric forensic pathology in Ontario was being released. After numerous issues came to light, the inquiry looked at policies, procedures, practices, accountability and oversight mechanisms, quality control measures and institutional arrangements within the field in Ontario from 1981 to 2001. Ontario Court of Appeal’s Honourable Justice Stephen T. Goudge developed 169 recommendations on how pediatric forensic pathology in Ontario needed to address and correct its systemic failings to restore public confidence.

(Read more about these inquiries here: https://www.attorneygeneral.jus.gov.on.ca/inquiries/goudge/index.html)

After studying the cases that prompted the inquiry and its recommendations in class, what left the greatest impression was the importance of having medicolegal autopsies performed by those trained in not just pathology, but specifically, forensic pathology. What I took away from the cases of accidental deaths falsely attributed as homicides due to lack of experience on behalf of the pathologist and other such issues, is that forensic pathology isn’t something to be dabbled in. While our patients are no longer alive, there are lives that can be affected by the work we do. In Ontario, false convictions not only stemmed from “junk science” but also from inadequacies in the training of pathologists working in a forensic capacity and also a general shortage of forensic pathologists.

Seems like a lot of us (of the few of us) who enter medical school knowing we want to go into pathology have to sort of wait their turn, as it were, collecting experiences which help make us competitive for residency matching—what keeps your “commitment algorithm” going?

Since discovering that forensic medicine is a career path as a high school student, I’ve geared my education towards training in forensics. First my undergraduate degree and then a side trip for my master’s degree in Forensic Death Scene Investigation and a job as a pathology technician at the Medical Examiner’s office on my way to medical school. I have in each step along the way, confirmed that both medicine and forensics fascinate me. Scroll through my Netflix account and you’ll find crime dramas (with the British shows being my favourite) or my podcast app filled with true crime shows; I am enraptured using science to figure out what happened.

Sidebar: at this point Kyla showed me a first-author published piece in the Journal of Forensic Sciences from 2017 that talked about law enforcement-involved firearm related deaths in Oklahoma, where she worked at the time. Basically, it showed through metadata analysis that gun-related deaths were on the rise. Not just over time, but number of times being shot. Remember when we talked about pathology’s role in the #StayInYourLane/#ThisIsOurLane discussion? Well which pathology speciality do you think works with this stuff directly? Chemistry? Cytology? Last time I checked GSWs don’t get screened for lead poisoning and you can’t FNA a bullet. Forensic pathology has often been tasked with seeing trends in morbidity and mortality and translating that to effective social and public health change: think seatbelts, stents, and maybe someday gun-related legislation changes.

Image 2a. Monthly aggregates of gun-related deaths over a 16-year period in OK. (Source: Jorgenson, K et al (2017) Trends in Officer-Involved Firearm Deaths in Oklahoma from 2000-2015, Journal of Forensic Sciences, doi: 10.1111/1556-4029.13499)
Image 2b. Number of gun shot wounds per victim over time. (Source: Jorgenson, K et al (2017) Trends in Officer-Involved Firearm Deaths in Oklahoma from 2000-2015, Journal of Forensic Sciences, doi: 10.1111/1556-4029.13499)

I was interested when I shadowed at the Cook County ME’s office a few years ago—I saw some cool things. I also remember learning a lot from the first real autopsy I saw in a hospital, ultimately it seems like a totally different field that maybe gets underappreciated even within the pathology umbrella. AP/CP residents have to do a certain number of autopsies to graduate, but the attitude I’ve noticed around the topic is a “necessary evil” and most are working towards not having to do that. So let me ask you definitively, why forensic pathology?

Medicine is science being applied to find out what happened in the body and how we can change or manipulate those variables to diagnose, prevent, treat and manage disease. Each diagnosis is solving a crime occurring within the cells in the body, if you will. In forensic medicine, not only do you get to do all that but add in the crime solving element and you get to be “Dr. Nancy Drew.” While medicolegal systems are different all over the US and Canada, chances are that as a forensic pathologist you won’t only be working on your stereotypical “forensics” cases, the gunshot wounds, stab wounds and other nefarious causes of deaths many associate with that term. You could get the generic, “cause of death atherosclerotic cardiovascular disease, manner of death natural,” for a large proportion of cases.

It’s not glamorous, you could spend your day with a two-week-old decomposing decedent that has a pulsating maggot mass devouring its torso or documenting 51 stab wounds or signing out your cases after reviewing your histology and toxicology reports or testifying on a homicide case you worked on. But for me, those all sound like pretty interesting ways to spend the day, sign me up. As a pathology technician assisting with the autopsies and external exams, I was never required to think about what was happening in the body, but I wanted to understand it all. Now as I progress through medical school and look towards residency and fellowship, I eagerly await the chance to perform my first autopsy as a physician, to put all the knowledge and experience I’ve gained towards helping move Ontario and forensic pathology forward.

Image 3. Kyla M. Jorgenson is a 3rd year medical student at the American University of the Caribbean School of Medicine with prior undergraduate and graduate studies in the field of forensic pathology, professional experience as an autopsy technician, as well as a vested interest in pursuing a career in the field moving forward in residency and fellowship. (Source: Kyla M. Jorgenson)

I’d like to thank Kyla for her time in talking with me and her willingness to share her insights with all of you. I wish her all the best of luck as she continues through her training with electives and core rotations both in the UK and state-side. If you have any questions to relay to her, please feel free to comment below and I will forward appropriately. And as always, don’t forget to share with your colleagues across every discipline!

Thanks for reading, I’ll see you next time where I’ll be writing from the Mayo Clinic Hospital in Rochester, Minnesota, conducting a formal rotation in Anatomic and Clinical Pathology! Don’t miss it, I’ll have lots to share while learning at one of the nation’s top institutions!

Until next time!

–Constantine E. Kanakis MSc, MLS (ASCP)CM graduated from Loyola University Chicago with a BS in Molecular Biology and Bioethics and then Rush University with an MS in Medical Laboratory Science. He is currently a medical student actively involved in public health and laboratory medicine, conducting clinicals at Bronx-Care Hospital Center in New York City.

Surgical Pathology Case Study: A 64 Year Old Man with History of Loose Stools and Abdominal Pain

Case History

A 64 year old male presented with a one year history of loose stools, lower abdominal crampy/gassy pain that improved with defection, and an unclear history of melena. A colonoscopy revealed a circumferential, villous, carpet-like lesion extending from 15 cm to the anal verge, with biopsies demonstrating fragments of a villous adenoma. A follow-up CT scan was negative for metastatic disease. The decision was then made to proceed with a low anterior resection with hand-sewn colo-anal anastomosis and diverting loop ileostomy.

Diagnosis

Upon opening the rectum, a 13.8 cm long circumferential, carpet-like lesion is identified, extending to the distal margin (Image 1). Sectioning demonstrated a lesion with a maximum thickness of 1.0 cm, which grossly appears to be confined to the mucosa. Due to the prior biopsy history of a villous adenoma, the entire lesion was completely submitted. This required 116 blocks to be submitted, which were then mapped out to show where each block would have been taken from (Image 2). Although there were many foci of intramucosal carcinoma present, clear cut submucosal invasion was not identified, and the specimen was signed out as a villous adenoma (Image 3).

Image 1. Opened rectum demonstrating the 13.8 cm-long carpet-like lesion.
Image 2. Mapping the lesion to show from where each block is taken.
Image 3. Photomicrograph showing the transition from normal mucosa (black arrow) to villous adenomatous tissue (red arrow).

Discussion

Polyps are an abnormal tissue growth that is a common occurrence within the colon, although they can also be found throughout the small intestine, stomach and esophagus. Polyps can be further classified as being neoplastic or non-neoplastic based on the histological pattern of the cells. The most common types of neoplastic polyps found within the GI tract are colonic adenomas, which are benign polyps that serve as precursors to the majority of colorectal cancers. Nearly half of adults in the Western world will develop adenomas by the age of 50, and there is no gender predilection. It is because of this that it is recommended that all adults get a colonoscopy by the age of 50 (even earlier when there is a family history of developing colorectal cancer).

Most polyps are small, measuring 0.5 cm or less, but can grow to be over 10 cm in size (as seen in this case). When a colonoscopy is performed, these polyps can appear as sessile, meaning flat, or pedunculated, meaning on a stalk. Due to the abnormal epithelial growth of the mucosa, the surface of an adenoma can have a velvety appearance, resembling that of a raspberry. Most patients will not demonstrate any symptoms from their polyps, with the exception of occult bleeding and anemia which are associated with larger polyps.

Dysplasia, which literally means “disordered growth”, occurs when the individual cells lose their uniformity and architecture, often resulting in cells with a hyperchromatic nuclei and a high nuclear to cytoplasmic ratio. The presence of dysplasia contained within the epithelium of a polyp is what classifies the polyp as an adenoma (Image 4). Based on their epithelial growth pattern, adenomas can be classified as either tubular adenomas or villous adenomas. Tubular adenomas tend to be smaller polyps, with a smoother surface and rounded glands on histologic examination. Villous adenomas, in contrast, tend to be larger polyps with long, slender villi noted on histology (Image 5). If an adenoma contains a mixture of tubular and villous elements, they are classified as tubulovillous adenomas. When a dysplastic cell is no longer contained within the epithelium, and instead breaches the basement membrane which separates the epithelium from the underlying tissue, it is termed invasive.

Image 4. Photomicrograph of the villous adenoma, demonstrating the dysplasia that is confined to the mucosa and not extending to the deeper tissue.
Image 5. Photomicrograph of the long, slender villi that are commonly seen in villous adenomas.

What makes this case so interesting is that there is a direct correlation between the size of an adenoma, and the risk of developing colorectal cancer. This is not true with most other cancers, however, as size plays no part in determining whether the tumor is cancerous or not. With colon polyps, the larger the polyp, the greater the chance of developing invasive carcinoma (i.e. cancer). This is why screening colonoscopies are so important. Studies have shown that regular colonoscopies, combined with the removal of the polyps found on the exam, reduce the incidence of colorectal cancer. Why this case is so interesting is that you could assume based on the size of this polypoid lesion, you would find some invasive component. However, after reviewing 116 blocks, not a single focus of invasion could be identified.

It should be stated that although there is a correlation between an adenomas size and the risk of developing cancer, the majority of adenomas will not progress to cancer, and in fact, there are no tools currently available that help to determine why one patient’s adenoma will progress to cancer, while another patient’s adenoma will not.

References

  1. Association of Directors of Anatomic and Surgical Pathology, adapted with permission by the American Cancer Society. Understanding Your Pathology Report: Colon Polyps (Sessile or Traditional Serrated Adenomas). cancer.org. https://www.cancer.org/treatment/understanding-your-diagnosis/tests/understanding-your-pathology-report/colon-pathology/colon-polyps-sessile-or-traditional-serrated-adenomas.html. Accessed February 14, 2019.
  2. Colon Polyps. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/colon-polyps/symptoms-causes/syc-20352875. Accessed February 14, 2019.
  3. Turner JR. Polyps. In: Kumar V, Abbas AK, Fausto N, Aster JC. Robbins and Cotran Pathologic Basis of Disease, 8th edition. Philadelphia, PA: Elsevier, Inc; 2010: 815-820

-Cory Nash is a board certified Pathologists’ Assistant, specializing in surgical and gross pathology. He currently works as a Pathologists’ Assistant at the University of Chicago Medical Center. His job involves the macroscopic examination, dissection and tissue submission of surgical specimens, ranging from biopsies to multi-organ resections. Cory has a special interest in head and neck pathology, as well as bone and soft tissue pathology. Cory can be followed on twitter at @iplaywithorgans.