Hematopathology Case Study: A 65 Year Old Male with a Skin Lesion on the Right Shoulder

Case History

A 65 year old Caucasian male presents with a skin lesion on his right shoulder. Physical examination reveals a 3 .0 cm  ×  1.5  cm hyperpigmented plaque with mild hyperkeratosis on his right shoulder and multiple scattered erythematous macules and plaques on the trunk and back Skin biopsy reveals involvement by Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN). PET scan reveals no extracutaneous involvement.

The patient undergoes CHOP chemotherapy followed by autologous hematopoietic stem cell transplantation. He is subsequently treated systemically with lanolidomide, venetoclax, and idelalisib due to relapses of disease.

The patient returns to clinic three years later for follow-up. While his original cutaneous lesions are completely resolved, new lesions are noted on his back (representative lesion, Image 1). Hematologic evaluation is remarkable for pancytopenia with hemoglobin 8.7gm/dL, white blood cells 1.4 K/uL, and platelets 39 K/uL. A biopsy of the bone marrow is performed.

Image 1. Skin lesion on back.

Biopsy Findings

Core biopsy
CD56
Aspirate

H&E stained sections demonstrate a normocellular bone marrow with diminished trilineage hematopoiesis and sheets of amphophilic, blastoid cells with irregular borders occupying most of the marrow cells. Immunohistochemistry demonstrates a cellular population with CD56. The aspirate smears show similar findings with numerous clustered blastoid cells (92%) with a monocytoid appearance, often with basophilic vacuolated cytoplasm. There is also a decrease in myeloid and erythroid precursors.

Flow cytometric analysis performed on the bone marrow aspirate reveals a dim CD45 population with expression of CD4, CD56, partial CD7, dim and partial CD5, and CD38. The same population lacks expression of immaturity markers such as CD34, MPO, and TdT. The morphologic and phenotypic findings found in the marrow specimen are diagnostic of extensive involvement of the marrow by BPDCN.

Discussion

BPDCN is a rare and highly aggressive malignancy derived from precursors of plasmacytoid dendritic cells. Its nomenclature has constantly changed over years as the understanding of this entity has been improved. It has been variously known as blastic natural killer cell lymphoma/leukemia, agranular CD4+ natural killer cell leukemia, and CD4+CD56+haematodermic neoplasm. It is currently classified under acute myeloid leukemia and related precursor neoplasms in the most recent WHO classification of tumours of haematopoietic and lymphoid organs.

Limited data exist regarding the incidence of BPDCN; however, it is estimated to account for 0.7% of primary cutaneous skin lymphomas and 0.44% of all hematological malignancies. This hematodermic malignancy predominantly affects elderly male patients with mean age ranging from 60 to 70; however, a few cases have also been reported in childhood and infancy. As demonstrated in our case, the patients typically present with multiple violaceous skin lesions, which may be associate with erythema, hyperpigmentation, purpura, or ulceration. Extracutaneous involvement is reported to occur in the bone marrow, peripheral blood, and lymph nodes.

Diagnosis of BPDCN relies on histological and immunophenotypic findings. Histologically, BPDCN may show a monomorphic infiltrate of medium-sized immature blastoid cells with round nuclei, finely dispersed chromatin, and cytoplasmic vacuoles. They typically display immunophenotypic expression of markers CD4, CD56, CD123, and T-cell leukemia/lymphoma 1 (TCL1) without any lineage-specific markers of T cells or B cells. Chromosomal abnormalities involving 5q, 12p,13q, 6q, 15q, and 9p have been reported. The differential diagnosis entails, but is not limited to, mature T-cell lymphoma, nasal-type NK/T-cell lymphoma, myeloid sarcoma/acute myeloid leukemia and T-cell lymphoblastic lymphoma/leukemia

The clinical course of BPDCN is aggressive, with a median survival of 9 to 16 months. The patients with disease limited to the skin may have a better prognosis, while advanced age and advanced clinical stage are indicators of poor prognosis.  There is currently no consensus on optimal management and treatment because of low incidence of BPDCN; however, most patients are treated with regimens used for other hematopoietic malignancies (i.e. CHOP and hyperCVAD) followed by allogeneic stem cell transplantation for eligible patients. They often respond well to chemotherapy with complete resolution of skin lesions; however, relapse of disease can occur due to resistance to chemotherapeutic agents, which may have happened in our case.

References

  1. Lim MS, Lemmert K, Enjeti A. Blastic plasmacytoid dendritic cell neoplasm (BPDCN): a rare entity. BMJ Case Rep. 2016;2016:bcr2015214093.
  2. Grushchak S, Joy C, Gray A, Opel D, Speiser J, Reserva, Tung R, Smith SE. Novel treatment of blastic plasmactoid dendritic cell neoplasm: a case report. Medicine (Baltimore). 2017 Dec;96(51):e9452.
  3. Dhariwal S, Gupta M. A case of blastic plasmacytoid dendritic cell neoplasm with unusual presentation. Turk J Haematol. 2018 Jul 24. doi: 10.4274/th.2018.0181.
  4. Shi Y, Wang E. Blastic plasmacytoid dendritic cell neoplasm: a clinicopathologic review. Arch Pathol Lab Med. 2014 Apr;138(4):564-9.
  5. Bulbul H, Ozsan N, Hekimgil M, Saydam G, Tobu M. Report on three patients with blastic plasmactoid dendritic cell neoplasm. Turk J Haematol. 2018 Sep;35(3):211-212.
  6. Kerr D 2nd, Sokol L. The advances in therapy of blastic plasmacytoid dendritic cell neoplasm. Expert Opin Investig Drugs. 2018 Sep;27(9):733-739.
  7. Pagano L, Valentini CG, Pulsoi A, Fisogni S, Carluccio P, Mannelli F, et al. Blastic plasmactoid dendritic cell neoplasm with leukemic presentation: an Italian multicenter study. Haematologic. 2013 Feb;98(2):239-246.

-Jasmine Saleh, MD MPH is a pathology resident at Loyola University Medical Center with an interest in dermatopathology and hematopathology. Follow Dr. Saleh on Twitter @JasmineSaleh.

-Kamran M. Mirza, MD PhD is an Assistant Professor of Pathology and Medical Director of Molecular Pathology at Loyola University Medical Center. He was a top 5 honoree in ASCP’s Forty Under 40 2017. Follow Dr. Mirza on twitter @kmirza.

Hematopathology Case Study: A 66 Year Old Man with Abdominal Pain and Diarrhea

Case History

66 year old man with a past medical history of Sjogren syndrome, hypertension and hypothyroidism presented to an outside hospital with abdominal pain and diarrhea. CT imaging showed extensive lymphadenopathy, splenomegaly, mesenteric thickening and ureteral dilatation, all highly concerning for lymphoma or other malignancy. A needle core biopsy of “mesenteric mass” showed reactive lymphoplasmacytic infiltrate in a sclerotic background. A second needle core biopsy of a retroperitoneal lymph node was performed which showed reactive features and numerous plasma cells. An excisional biopsy of an inguinal lymph node was ultimately performed due to worsening lymphadenopathy with increased PET FDG avidity.

Excisional Biopsy

H&E 10x
H&E 20x
H&E 20x
H&E 40x
IgG
IgG4

Diagnosis

At low power view, there is intact follicular architecture with reactive appearing germinal centers that are polarized and show tingible body macrophages. The higher power view shows a feature that can be seen in Castleman disease called a “lollipop” which has a thickened vessel with hypertrophied endothelial cells penetrating the germinal center. In addition, there are areas with sclerotic remnants of germinal centers, a feature that can be seen in infection or other reactive conditions. Notably, the interfollicular space is expanded by numerous plasma cells and rare scattered eosinophils. Overall, the lymph node shows reactive follicular and paracortical hyperplasia. Stains for IgG and IgG4 showed an elevated IgG:IgG4 ratio with 54% of IgG plasma cells positive for IgG4. These findings raise the possibility of IgG4-related lymphadenopathy (IgG4LAD). In addition to histopathologic findings, the patient was tested for a serum IgG4 level, which is an important diagnostic criterion for the diagnosis of IgG4 disease. Seen above, serum testing on 10/25/18 showed a low/normal IgG subclass 4 of 17 mg/dl. After the excisional biopsy was performed, suspicion of involvement by IgG4-related disease increased. A sample was re-sent on 11/27/18 with instructions to perform serial dilutions in case of the prozone effect (see discussion below). The test came back with an elevated serum IgG subclass 4 of 1239 mg/dl, further supporting the diagnosis of IgG4-related disease.

Discussion

IgG4-related disease is a condition that was originally described in patients with autoimmune pancreatitis. These patients were found to have elevated serum IgG4 concentrations and have large numbers of IgG4-positive plasma cells. IgG4-related disease is now recognized as a fibroinflammatory condition and has been described in almost every organ system. Similar histopathological characteristics can be seen regardless of location and include tumefactive lesions, dense lymphoplasmacytic infiltrate, increased IgG4-positive plasma cells and storiform fibrosis.1

IgG4 normally accounts for less than 5% of the total IgG in healthy people and is the least abundant IgG subclass. IgG4 is also seen to be involved in other immune-mediated conditions such as pemphigus vulgaris, idiopathic membranous glomerulonephritis, and thrombotic thrombocytopenic purpura. The majority of patients with IgG4-related disease have elevated serum IgG4 concentrations, but 30% of patients may have normal IgG4 concentrations.1 When testing IgG4 serum levels, it is important to be aware of the prozone effect. This occurs when very high concentrations of the antibody that is being measured are present. This will prevent appropriate antibody-antigen binding and agglutination from occurring. This will result in a falsely low level of antibody being detected. In a report by Khosroshahi et. al., after identifying the prozone effect in one patient with IgG4-related disease, 38 patients who had previously been tested for serum IgG4 levels were re-tested. The prozone effect was found to affect 26% of patients with IgG4-related disease. The samples were re-tested with serial dilutions and the mean serum concentration rose from 26 mg/dl to 2,008 mg/dl. This could have a large impact on patient care, as elevated serum IgG4 concentrations are very important in making the diagnosis of IgG4-related disease. 2

IgG4-related lymphadenopathy (IgG4LAD) is somewhat distinct from tissue based IgG4-related disease and presents with solitary or multifocal lymph node enlargement. Lymph nodes are involved by a lymphoplasmacytic infiltrate with increased IgG4-positive plasma cells and tissue eosinophils and are not typically involved by storiform fibrosis. Five microscopic subtypes have been described and include multicentric Castleman disease-like changes, follicular hyperplasia, interfollicular lymphoplasmacytic proliferation, progressive transformation of germinal centers, and a variant with the formation of inflammatory pseudotumor-like lesions. The differential diagnosis of this entity is broad and purely reactive lymph nodes as well as multicentric Castleman disease (MCD), in particular needs to be ruled out. The presence of HHV8 infection and elevated IL-6 and CRP can favor MCD, while tissue eosinophilia favors IgG4LAD.3    

The diagnostic criteria for the diagnosis of IgG4LAD includes lymph node involvement,  a serum IgG4 level greater than 135 mg/dl, and histologic findings of lymphoplasmacytic infiltrates with either >10 IgG4-positive plasma cells per hpf or a ratio of IgG4-positive to IgG-positive plasma cells to be greater than 40%. As seen in this case, patients may undergo multiple biopsies, often with extensive work-ups before a diagnosis is made. Treatment depends on the organ involved and extent of damage/dysfunction. While some cases may only need clinical follow-up, others will require urgent aggressive treatment. Glucocorticoids are typically the first line of therapy and have been shown to be effective in a majority of patients with IgG4-related disease. 3

References

  1. Stone, J, Zen, Y, Deshpande, V. IgG4-Related Disease. N Engl J Med 2012; 366:359-551.
  2. Khoroshahi, A, Cheryk, LA, Carruthers, MN, et. al. Brief Report: spuriously low serum IgG4 concentrations caused by the prozone phenomenon in patients with IgG4-related disease. Arthritis Rheumatol 2014; 66(1):213-7.
  3. Wick, M, O’Malley, D. Lymphadenopathy associated with IgG4-related disease: Diagnosis and differential diagnosis. Seminars in Diagnostic Pathology 2018; 35(1)61-66.

Chelsea Marcus, MD is a third year resident in anatomic and clinical pathology at Beth Israel Deaconess Medical Center in Boston, MA and will be starting her fellowship in Hematopathology at BIDMC in July. She has a particular interest in High-grade B-Cell lymphomas and the genetic alterations of these lymphomas.

Hematopathology Case Study: A 23 Year Old Man with Epistaxis, Fever and Pancytopenia

Case History

A 23 year old man presented to the hospital with recurrent fever up to 103F with associated nausea and vomiting, epistaxis, watery diarrhea, dyspnea, and decreased appetite for several days. Blood cultures from admission were positive for MSSA and a stool PCR was positive for Vibrio species. He was admitted and treated for sepsis. His CBC demonstrated a marked pancytopenia ( WBC count 0.6 K/μL) and the hematopathology team was consulted to review the peripheral blood film.

Peripheral blood smear.

Review of the peripheral blood confirmed a markedly pancytopenic picture with virtually no leukocytes in the region of best RBC “spread” (Image 1A). In the periphery of the smear (1B and C) clusters of leukocytes were noted where left-shifted granulocytes were seen. Many demonstrated nuclear irregularity and abnormal granulation (B) and some showed the presence of numerous Auer rods (Image 1C, arrows).

The presence of abnormally granulated immature neutrophilic precursors, and cells with numerous Auer rods was morphologically compatible with acute promyelocytic leukemia (APL) and a rush preliminary diagnosis was rendered. The patient was started on ATRA therapy and FISH for PML-RARA was expedited.

Discussion

Acute promyelocyticleukemia (APL) is characterized as an acute myeloid leukemia in which promyelocytes with the PML-RARA fusion predominate. The PML-RARA fusion is the result of a balanced translocation between chromosomes 15 and 17, designated ast (15;17)(q24.1;q21.2).  The promyelocyte progenitor cell is the cell of origin of APL. APL occurs most frequently in middle aged individuals, but can occur at any age.

The first account of APL was originally discussed in the late 1950s in which L. K.Hillestad, a hematologist from Norway, described a disorder as “a white blood cell picture dominated by promyelocytes and severe bleeding caused mainly by fibrinolysis.” The gene fusion was elucidated in the late 1970s at the University of Chicago demonstrating the balanced translocation between chromosomes 15 and 17. Cure rates at that time were still very low, until in the mid 1980s when researchers in China demonstrated the use of all-trans retinoic acid causing complete remission in APL patients.

Two distinct subtypes of APL exist: hypergranular (typical) or microgranular. The hypergranular variant is filled with large Auer rods and with dense cytoplasmic granules that can obstruct the nucleus. In contrast, the microgranular variant has a scantiness of cytoplasmic granules or small azurophilic granules.

The immunophenotype for APL is quite distinct and characterized by low or absent expression of CD34 and HLA-DR (in keeping with the cellular differentiation from blast to promyelocyte). APL cells are positive CD33 and CD13 with most cases showing expression of CD117 (sometimes weak). APL cells are usually negative for CD15, CD65, CD11a, CD11b, and CD18. The microgranular variant may display positive staining for CD34 and CD2. For both variants, IHC with antibodies to the PML gene demonstrates a nuclear multi granular pattern with nucleolar exclusion, a finding that is unique to APL and not seen in AML or normal promyelocyte morphology.

The main clinical symptom of APL is hemorrhagic, including gingival bleeding and ecchymosis but can progress to disseminated intravascular coagulopathy (DIC). Other symptoms of APL include those related to pancytopenia, including weakness, fatigue, and infections.

The prognosis for APL is considered to be excellent. Tretinoin (ATRA) interacts with the PML-RARA fusion product allowing for maturation and differentiation to occur along the granulocytic lineage, eliminating the promyelocyte population. Combination therapy with tretinoin and arsenic trioxide has become the gold standard of care leading to excellent remission rates.

References

  1. Kakizuka,A., et al. “Chromosomal translocation t (15; 17) in human acutepromyelocytic leukemia fuses RARα with a novel putative transcription factor,PML.” Cell 66.4 (1991): 663-674.
  2. Lo-Coco,Francesco, and Laura Cicconi. “History of acute promyelocytic leukemia: atale of endless revolution.” Mediterranean journal of hematologyand infectious diseases3.1 (2011).
  3. Rowley,JanetD, HarveyM Golomb, and Charlotte Dougherty. “15/17 translocation, aconsistent chromosomal change in acute promyelocytic leukaemia.” TheLancet 309.8010 (1977): 549-550.
  4. Swerdlow,Steven H. WHO Classification of Tumours of Haematopoietic and LymphoidTissues. International Agency for Research on Cancer, 2017.

-Christopher Felicelli is an M3 at Loyola University Chicago Stritch School of Medicine. Follow Chris on Twitter at @ChrisFelicelli

-Kamran M. Mirza, MD PhD is an Assistant Professor of Pathology and Medical Director of Molecular Pathology at Loyola University Medical Center. He was a top 5 honoree in ASCP’s Forty Under 40 2017. Follow Dr. Mirza on twitter @kmirza.

Hematopathology Case Study: A 54 Year Old Woman with a Bone Fracture

Case History

The patient is a 54 year old woman who presented to the hospital after a fall, which revealed a pathologic fracture of T1 and a spinal lesion from C6/C7 to T2. CT of the chest/abdomen and pelvis at the time showed a large mass in the anterior mediastinum with extensive lymphadenopathy and lytic lesions in the spine and ribs.

C7-T1 Soft Tissue Excision

H&E 20X
H&E 50X
H&E 100X
CD30
BSAP/PAX5
KI-67

Diagnosis

Sections show sheets of large epithelioid-like cells with segmented nuclei with variably prominent nucleoli and ample amounts of eosinophilic cytoplasm.A majority of these larger cells have abundant cytoplasm and lobulated nucle iwith multiple nucleoli and a surrounding halo. They are consistent with Lacunar cells. These cells form large aggregates and are admixed with numerous neutrophils, histiocytes and scattered lymphocytes.

Occasional Hodgkin cells and multi-nucleated Reed-Sternberg cells are seen, as well as scattered medium size hyper chromatic cells with irregular nuclear contours and scant cytoplasm consistent with mummy cells.

Immunohistochemical staining revealed that the largea typical cells are immunoreactive for CD30, CD15 and PAX5/BSAP. CD45 highlighted background lymphocytes but showed infrequent dim staining in the large atypical cells. By Ki-67, the proliferation index is 50-60% in the large atypical cells. Taken together, the findings are consistent with Classic Hodgkin Lymphoma, nodular sclerosis, syncytial variant.

Discussion

Classic Hodgkin lymphoma (CHL) has four distinct subtypes including nodular sclerosis, lymphocyte-rich, mixed cellularity and lymphocyte-depleted. These subtypes differ based on characteristics of the background non-neopalastic reactive cells and the histomorphology of the Hodgkin/Reed-Sternberg cells (HRS). Nodular sclerosis Classic Hodgkin lymphoma accounts (NSCHL) for approximately 70% of all CHLs. The mediastinum is the most commonly involved site and it generally occurs in people between the ages of 15-34 years old. Generally, the histology shows nodules with surrounding fibrosis. There are a variable number of Hodgkin/Reed-Sternberg (HRS) cells mixed with other inflammatory cells. The characteristic HRS cell is called a lacunar cell. This is a type of HRS cell with more cytoplasm, less prominent nucleoli and can show retraction of the cytoplasm in formalin-fixed tissue that gives the cell a halo or “lacunae.”1

The syncytial variant (SV) of CHL, nodular sclerosis was first described in the 1980s. It presents in 5-15% of cases of NS CHL. It is characterized by sheets and clusters of “lacunar cells” typical of the type of HRS cell most commonly seen in NS CHL. Previous studies had determined the SV of CHL to have a worse prognosis and more aggressive course than other subgroups. In a more recent study by Sethi, et. al. the clinical features and response to treatment of patients with SV were compared to patients with typical NS CHL. Within the cohort, 43 patients with SV were compared to 124 patients with typical NS CHL. The study found that there was no significant difference in age, sex, performance status, stage, bulky disease, number of nodal sites and chemotherapy regimens used between the two groups.2

As far as treatment outcomes, the rate of complete response in the SV group was 74% vs. 87% in the NS group. This result approached statistical significance with a p=0.05. The medium progression-free survival in the SV group was significantly shorter compared with the NS group. The overall survival, however was not statistically different, indicating that salvage chemotherapy was ultimately able to match the clinical outcomes for patients with SV type to patients with NS type. 2

Currently, all CHLs are treated with adriamycin, bleomycin,vinblastine, decarbazine (ABVD) chemotherapy regimen plus or minus radiation therapy regardless of subtype. Patients with relapsed or refractory disease are treated with a “salvage” chemotherapy regimen followed by an autologous stem cell transplant. Emerging therapies including PD-1 inhibitor nivolumab have shown great effect in patients with CHL. PD-1 or programmed death ligand 1 is overexpressed on HRS cells. This ligand binds with receptorson T-cells to prevent the T-cell immune response and reduce cytokine activation and targeted  response against the proliferating HRS cells. By using an antibody against the PD-1 ligand in CHL,the ability of the tumor to suppress the immune response is decreased and patients have been shown to have better clinical response rates.3

Patients with SV do need to be recognized as a distinct subgroup that may have a higher risk of disease progression with first line chemotherapy agents.  Due to the high numbers of HRS cells seen in patients with SV and the increased failure rate of initial chemotherapy agents, antibody therapies such as PD-1 inhibitors may be even more successful in those patients.

References

  1. Swerdlow SH, Campo E, Harris NL, et al. WHO Classification of Tumours of Haematopoetic and Lymphoid Tissues (Revised 4thedition). IARC: Lyon 2017.
  2. Sethi, T.K.,  et al. Differences in Outcome of Patients with Syncytial Variant Hodgkin Lymphoma (HL) Compared with Typical Nodular Sclerosis HL. Blood. 2015;126(23),1441. Retrieved from http://www.bloodjournal.org/content/126/23/1441.
  3. Bond DA, Alinari L. Emerging treatment options for the management of Hodgkin’s lymphoma:clinical utility of nivolumab. J Blood Med. 2017;8:41-54. Published 2017 May 11. doi:10.2147/JBM.S117452.

Chelsea Marcus, MD is a third year resident in anatomic and clinical pathology at Beth Israel Deaconess Medical Center in Boston, MA and will be starting her fellowship in Hematopathology at BIDMC in July. She has a particular interest in High-grade B-Cell lymphomas and the genetic alterations of these lymphomas.

Hematopathology Case Study: A 56 Year Old Man with Sinus Congestion and Axillary Adenopathy

Case History

A 56 year old male presented to his PCP complaining of sinus congestion, rhinorrhea, night sweats, decreased appetite and fevers of up to 101-102 every evening. Hematologic evaluation revealed a neutropenia and a lymphopenia. An infectious disease work up was negative. His LDH was elevated. Physical examination reveals an enlarged left axillary lymph node. An excisional biopsy was performed.

Biopsy Findings

Figure 1.jpg

Figure 2.jpg

H&E stained sections demonstrate an enlarged node with effaced architecture and scattered residual follicles with small, mature cells. There is a proliferation of intermediate to large, to very large, atypical and highly pleomorphic cells many of which demonstrate bizarre forms, irregular nuclear morphology and acidophilic nucleoli. The lymphoma cells are noted to focally traverse through adipose tissue. Occasional hallmark cells are appreciated.

To further characterize the infiltrate, immunohistochemical stains were performed and interpreted with appropriate controls. The lymphoma cells were diffusely positive for CD45 (LCA), CD43, and CD30 (membranous and Golgi) with a Ki-67 of 80-90%. These cells were negative for CD20, PAX-5, CD3, CD4, CD8 (mostly), CD5, D10, BCl-2, BCl-6 and ALK1.

The morphologic features and immunophenotype of the cells was diagnostic of anaplastic large cell lymphoma, ALK negative.

Discussion

Anaplastic Large Cell Lymphoma (ALCL), ALK-negative (ALK-) is defined as a CD30+ T-cell neoplasm that morphologically resembles ALK-positive ALCL, but lacks ALK protein expression. It most commonly affects adults (aged 40-65 years), and has a slight male preponderance with a male-to-female ratio of 1.5:1. T. Most patients present with advanced disease (stage III-IV), lymphadenopathy and B symptoms. The most common differential diagnosis is ALK-positive ALCL.

The molecular deciphering of ALCL began in the 1990s with the discovery of a recurrent t(2;5) (p23;q35) translocation fusing the ALK gene and the nucleophosmin gene generating a NPM-ALK fusion protein, as well as other ALK translocations resulting in a high ALK kinase activity. This triggers the major oncogenic pathway in ALK-positive ALCL. Pharmacologic therapy has been developed to target ALK, and has shown efficacy. Thus, compared with ALK-negative cases, ALK-positive occurs in younger patients and has a better prognosis. ALK-negative ALCL also tends to involve both lymph nodes and extranodal tissues, although extranodal sites are less commonly involved than in ALK+ ALCL.

The other differential diagnoses of ALK- ALCL includes, primary cutaneous ALCL (C-ALCL), other subtypes of CD30+ T-cell or B-cell lymphoma with anaplastic features and classic Hodgkin Lymphoma. If a single lymph node or cutaneous cases are suggestive of ALK- ALCL, C-ALCL needs to be considered. Any cases that involve the gastrointestinal tract need to be distinguished from CD30+ enteropathy-associated and other intestinal T-cell lymphomas.

Molecular analysis of ALK- ALCL shows characteristic strong expression of CD30, in equal intensity in all the cells. Loss of T-cell markers is frequently seen, however, more than half of all cases express one or more T-cell markers. CD2 and CD3 are more commonly expressed than CD5, and CD43 is almost always expressed. CD4+ is frequently positive, while CD8+ is rare. Many cases also express cytotoxic markers TIA1, granzyme B, and/or perforin.

The genetic profile in ALK-negative ALCL has been found to be pretty heterogenous. Most notably, activating mutations of JAK1 and/or STAT3 have been shown to lead to activation of the JAK/STAT3 pathway. Chromosomal rearrangements of DUSP22 (i.e. chromosomal rearrangements in or near the DUSP22-IRF4 locus on 6p25.3) occur in 30% of the cases, and rearrangements of TP63 occur in about 8% of cases. Neither of the rearrangements have been reported in ALK+ ALCL.

From a prognostic standpoint, studies have shown that the rearrangements have effects on the survival rate. TP63-rearranged cases were shown to have an unfavorable prognosis worse than ALK- ALCL with neither rearrangement, while DUSP22-rearranged cases were shown to have favorable outcomes similar to ALK-positive ALCLs.

References

  1. Gaulard P, de Leval L. ALK-negative anaplastic large-cell lymphoma. 2016 Jan 14;127(2):175-7.
  1. Edgardo R. Parrilla Castellar et al., ALK-negative anaplastic large cell lymphoma is a genetically heterogeneous disease with widely disparate clinical outcomes Blood. 2014 Aug 28; 124(9): 1473–1480.

 

Bradon Zelman

-Brandon Zelman is 4th year medical student at the Philadelphia College of Osteopathic Medicine and an aspiring pathologist. You can follow Brandon on Twitter @ZelmanBrandon.

Mirza-small

-Kamran M. Mirza, MD PhD is an Assistant Professor of Pathology and Medical Director of Molecular Pathology at Loyola University Medical Center. He was a top 5 honoree in ASCP’s Forty Under 40 2017. Follow Dr. Mirza on twitter @kmirza.

Hematopathology Case Study: A Newborn Infant with a High White Blood Cell Count

Case History

The patient is a 1 day old baby boy born at 39 weeks to a 44 year old woman. On physical examination, the baby had a mildly flattened occiput with thickened nuchal skin, downward slant of palpebral fissures with epichanthal folds and slightly low set ears. On imaging, he had a ventricular septal defect. A CBC was performed which revealed a white count of 34.2 K/uL with a differential that included 37 blasts.

Peripheral Blood Smear 

TAM1.jpg

TAM2

Cytogenetics

TAM3

TAM4.JPG

Diagnosis

The peripheral blood showed an increased white count, many nucleated red blood cells as well as a population of blasts. The cytogenetic analysis confirmed the suspicion of trisomy 21. Flow cytometry showed that the population of blasts expressed myeloid as well as erythroid and megakaryocytic lineage specific antigens. The patient was found to have a GATA1 mutation. Approximately one month after birth, the patient’s white count normalized to 7.2 K/uL with only 4 circulating blasts counted.

Discussion

In a patient with trisomy 21, this presentation is consistent with a diagnosis of transient abnormal myelopoiesis associated with Down syndrome (TAM). TAM occurs in 10% of newborns with Down syndrome. Patients typically present with cytopenias, leukocytosis, an increase in blasts and hepatosplenomegaly. Less commonly, patients can have respiratory distress, bleeding, skin rash or jaundice. The blasts are morphologically and immunophenotypically similar to those seen in acute myeloid leukemia. They often have basophilic cytoplasm, coarse basophilic granules and cytoplasmic blebbing, which suggests a megakaryocytic lineage. The immunophenotype generally includes expression of myeloid markers such as CD117, CD13 and CD33 plus erythroid and megakaryocytic markers like CD41, CD42b and CD61.1

In addition to trisomy 21, mutations in GATA1 are almost always seen in the blast cells of patients with TAM. GATA1 is a hematopoetic transcription factor. Bhatnagar, et al. (see diagram below) describe a three step model to explain the evolution of TAM. The initial event is abnormal hematopoesis in the fetal liver caused by trisomy 21. This causes an increase in megakaryocyte-erythroid progenitors in the hematopoetic stem cell compartment.  The second step is the acquisition of an N-terminal truncating GATA1 mutation before birth. GATA1 is a regulator of normal megakaryocyte and erythroid differentiation. The truncated mutation causes marked expansion of megakaryoblastic progenitors.

TAM5TAM has a high rate of spontaneous remission and typically resolves spontaneously in 90% of patients over several weeks to 6 months. This coincides with extinction of the GATA1 clone. However, in around 10% of these patients, myeloid leukemia of Down syndrome (ML-DS) develops within 5 years of the initial presentation. Additional mutations in cohesion component genes and epigenetic regulators occur in these patients that result in clonal expansion and non-transient leukemia. 2 Children who develop ML-DS generally have a good response to chemotherapy and a have a better prognosis than children without Down syndrome who develop AML.

References

  1. Swerdlow SH, Campo E, Harris NL, et al. WHO Classification of Tumours of Haematopoetic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017.
  2. Bhatnagar, Neha et al. “Transient Abnormal Myelopoiesis and AML in Down Syndrome: An Update.” Current Hematologic Malignancy Reports5 (2016): 333–341. PMC. Web. 21 Oct. 2018.

 

Marcus, Chelsea_099-Edit

Chelsea Marcus, MD is a third year resident in anatomic and clinical pathology at Beth Israel Deaconess Medical Center in Boston, MA and will be starting her fellowship in Hematopathology at BIDMC in July. She has a particular interest in High-grade B-Cell lymphomas and the genetic alterations of these lymphomas.

 

 

Hematopathology Case Study: A 63 Year Old Man with Fatigue

Case history

A 63 year old male presented with extreme fatigue and weakness of unknown duration. Physical examination revealed scattered petechiae and mildly decreased muscle strength. His past medical history included a one year history of cough that had recently improved. Laboratory investigation demonstrated severe anemia and thrombocytopenia with a mild leukopenia.

Review of the peripheral blood smear showed smudge cells, circulating neutrophils with Döhle bodies and toxic granulation. CT scan of the chest showed upper/anterior mediastinal lymphadenopathy without hilar lymphadenopathy.

A biopsy of the bone marrow was performed.

Microscopic Findings

hod1.jpg

 

hod 2.jpg

The bone core biopsy revealed a hypercellular marrow for the patient’s age with a pronounced lymphohistiocytic infiltrate involving 30-40% of the biopsied marrow space. Interspersed along the infiltrate were large, atypical lymphoid cells with pleomorphic nuclei and prominent nucleoli. The marrow aspirate smear reveals progressive trilineage hematopoiesis with scattered hemophagocytic histiocytes.

Immunophenotype

hod3.jpg

The large atypical lymphoid cells were positive for CD30 and EBER, while being dimly positive for PAX5 and negative for CD20.

Diagnosis

The detection of mononuclear Hodgkin cells staining for CD30 along with a characteristic reactive infiltrate, together with dim PAX-5 staining, positive EBER, and negative CD20 is sufficient to diagnose involvement of a secondary site by Hodgkin lymphoma. The lymphoma was associated with a secondary hemophagocytic lymphohistiocytosis.

Discussion

Hodgkin lymphoma (HL) is a B-cell derived monoclonal lymphoid neoplasm. HL has a bimodal age distribution, with teenagers or patients in their early 20s and patients older than 55 years having the highest incidence. Although the typical presentation is with peripheral lymph node involvement, extranodal sites may be involved by either direct invasion or hematogenous dissemination. These sites include the spleen, liver, lung and bone marrow. About one third of patients have constitutional symptoms such as high fevers, night sweats, and weight loss.

Two broader forms of Hodgkin lymphoma exist: Classic Hodgkin lymphoma (CHL) and the less common nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). NLPHL tends to preserve the entire B-cell transcriptional phenotype, while the neoplastic cells in CHL fail to do so.

CHL is composed of mononuclear Hodgkin cells and multinucleated Reed-Sternberg cells surrounded by an infiltrate of non-neoplastic reactive cells that might encompass small lymphocytes, plasma cells, eosinophils, neutrophils, and histiocytes. Fibrosis may also be present in the form of bands or may be more diffusely spread. The four histological subtypes: nodular sclerosis CHL, lymphocyte-rich CHL, mixed cellularity CHL, and lymphocyte-depleted CHL are based on the composition and characteristic of the reactive infiltrate, and the cytological features of the neoplastic cells.

The classic Reed-Sternberg cell is binucleated, with prominent eosinophilic nucleoli, often referred to as having an “owl’s eye” appearance. However many neoplastic cells are not of the typical Reed-Sternberg variant, and can be mononuclear, termed Hodgkin cells, or cells with more condensed cytoplasm and pyknotic reddish nuclei known as mummified cells.

Hodgkin/Reed-Sternberg cells (HRS) in Classic Hodgkin Lymphoma fail to preserve their B-cell traits, and this is reflected by their immunophenotype. The majority of cases are negative for CD45, and although CD20 may be expressed, it is usually present only on a minority of the neoplastic cells and stain with varied intensity. The HRS cells stain with PAX5 with a lower intensity than the surrounding reactive cells, making them easily detectable. The HRS cell stains positive for CD30 and CD15 in nearly all cases. Both of them stain the membrane with accentuation around the Golgi apparatus. EBV associated Hodgkin Lymphoma will stain positive with EBER, detecting EBV-encoding small RNA.

Bone marrow involvement is rare, ~5-10% of cases, and suggest vascular dissemination of the disease. Bone marrow trephine biopsies are commonly performed in the staging of patients with newly diagnosed CHL which guides the further treatment and gives us information about prognosis. Involvement of the bone marrow represents stage IV disease (advanced stage) in the Ann Arbor staging classification and patients with advanced stage disease typically receive a more prolonged course of chemotherapy. The 5-year survival rate of stage IV Hodgkin lymphoma is ~65%,  a much worse prognosis when compared with stage I, stage II, and stage III with ~90%, ~90%, and ~80% 5-year survival rates respectively.

References

  1. Stein H, Pileri SA, Weiss LM, et al. Hodgkin Lymphomas. In Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, editors: WHO classification of tumours of haematopoietic and lymphoid tissues, revised ed 4, Lyon, France, 2017, IARC Press, pp 423-464
  2. Ansell SM. Hodgkin Lymphoma: Diagnosis and Treatment. Mayo Clin Proc. 2015 Nov;90(11):1574-83.
  3. Howell SJ, Grey M, Chang J, Morgenstern GR, Cowan RA, Deakin DP, Radford JA. The value of bone marrow examination in the staging of Hodgkin’s lymphoma: a review of 955 cases seen in a regional cancer centre. Br J Haematol. 2002 Nov;119(2):408-11.
  4. Clarke C, O’Malley C, Glaser S. Hodgkin lymphoma. In: Ries LAG, Young JL, Keel GE, Eisner MP, Lin YD, Horner M-J, eds. SEER Survival Monograph: Cancer Survival Among Adults: U.S. SEER Program, 1988-2001, Patient and Tumor Characteristics. National Cancer Institute, SEER Program, NIH Pub. No. 07-6215, Bethesda, MD, 2007.

 

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-Hans Magne is a 6th- year medical student at Poznan University of Medical Sciences. Follow Hans on Twitter @HHamnvag

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-Kamran M. Mirza, MD PhD is an Assistant Professor of Pathology and Medical Director of Molecular Pathology at Loyola University Medical Center. He was a top 5 honoree in ASCP’s Forty Under 40 2017. Follow Dr. Mirza on twitter @kmirza.