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.


Adventures in Grossing, Part I

So its no secret that I don’t feel that I’m the world’s best or fastest grosser. I didn’t read Lester or Westra (aka the grossing Bibles) as much as I should’ve first year and still have never finished either cover to cover. And the fact that we had surgpath fellows stand by our side and teach us how to gross initially was probably more of a crutch for me than I should’ve allowed it to be. I need to understand why I should gross a specimen a specific way because memorizing the steps does not work for me – because I forget the next time and because not every specimen is “perfect” and I may need to modify the general protocol.

But for the past two months, I’ve been at our program’s busiest surgpath site, a private practice in a community hospital setting that sees a whole lot of cancers. My first day definitely was not a good one. I had spent 10 hours traveling from USCAP back to my apartment and had gotten a mild migraine in between…so much so that I got off at my layover asking if I could take a later flight back. Unfortunately, the next flight would get me home close to 7 AM and it’s a 1-1.5 hour drive to this hospital for me during rush hour traffic. This site is close to the airport so I would’ve been better off going straight from there.

It was the perfect storm, both figuratively and literally. I was tired from travel and nursing the residual headache that always follows one of my migraines… it was snowing yet again…and this caused a few accidents…and for me to be late my first day at this site after I had missed the first two days of the rotation (which is generally a no-no). So my first impression was most definitely not a good one. Couple that with being assigned grossing duty for a moderately heavy day, not knowing where anything was or how things were supposed to be done at this site, not being able to access the EMR, and not knowing what my responsibilities were versus those of the tech assigned to stand by and assist me (at other sites, I had to do everything by myself), and its not surprising that I failed to impress my attending.

VoiceBrook (Medical Dragon dictation software), the bane of my existence right now, was not working and their staff kept calling since there was miscommunication about my appointment to re-train with VoiceBrook. On top of all of this, I didn’t get to do the compensatory rituals I usually do to feel less stressed about grossing – work up my patients/specimens ahead of time, read Lester and Westra, and triage my grossing day based on the OR schedule. I pretty much felt like a “robot” (a sick one at that) that went straight through the manual motions of continuous grossing until the time came to close the gross room.

The attendings at this site have very specific ideas of the “right way” to gross and their expectations varies from the other in terms of their views on these topics. It is very busy in terms of grossing, intraoperative consultations, and weekly tumor boards that the residents prepare and present. But this post is actually not to complain but to elaborate on a light bulb moment that I had today that I had subconsciously somewhat improved my speed and many of the gaps in my understanding of what to gross and how to do it. Sometimes, repetition can be a great teacher. Good communication with those you work with is key. And lastly, nothing beats a good mentor who is willing to work with you to address your weaknesses… so what were your light bulb moments during your most difficult rotation and how did you come to recognize them? I’ll continue next week with a little more on this topic but for now, its bedtime since I anticipate a busy grossing day tomorrow.

 

Chung

Betty Chung, DO, MPH, MA is a second year resident physician at the University of Illinois Hospital and Health Sciences System in Chicago, IL.