Monitoring Editor: Alexander Muacevic and John R Adler
Farhan Mohammad, Gwenalyn Garcia, Shiksha Kedia, Juan Ding, Matthew Hurford, and Alexander Bershadskiy
Abstract Composite lymphoma is an extremely rare clinical entity and is characterized by the presence of two different subtypes of lymphoma in the same lymph node. We report a case of composite lymphoma in a 57-year-old male presenting with leg and groin pain. The right inguinal lymph node biopsy showed large and small cells. Immunohistochemistry was consistent with large cells staining for diffuse large B-cell lymphoma (DLBCL) and small cells positive for mantle cell lymphoma (MCL). Polymerase chain reaction (PCR) analysis of immunoglobulin heavy (IGH) chain and immunoglobulin kappa (IGK) light chain gene rearrangements confirmed that the two were clonally unrelated neoplasms. There are only two reported cases of composite lymphoma with this combination in the published English literature. We report the third such case and discuss the pathology, diagnostic challenges and management of composite lymphoma. Introduction Composite lymphoma is defined by the presence of two distinct architectural and cytological subtypes of lymphoma occurring within the same lymph node. The majority of reported composite lymphomas represent two forms of non-Hodgkin lymphoma (NHL), e.g., mixed small and large cell lymphoma. The rare association we discuss is the presence of Hodgkin lymphoma and NHL in the same lymph node. It is believed that Hodgkin lymphoma and NHL represent mutually exclusive clinicopathological entities. Herein, we present a case of composite lymphoma consisting of diffuse large B-cells and small cells of mantle cell lymphoma. Consent was obtained from the patient for the publication of this report.
Case presentation
A 57-year-old male with a history of hypertension and benign prostatic hypertrophy presented with complaints of decreased appetite, leg cramps with associated discomfort in his right groin and swelling in the right leg. The patient also reported fatigue with a 10-pound weight loss over the preceding month. He denied fever, chills or night sweats. On physical examination, the spleen was palpable one finger breadth below the costal margin with mild adenopathy in the right and left inguinal regions. Pitting edema in the left lower extremity was present. A computed tomography (CT) scan of the abdomen and pelvis revealed a large conglomeration of lymph nodes involving the right periaortic region extending to the right pelvic side wall with areas of central necrosis. Also seen was a right inguinal lymph node measuring about 2.8 x 2.1 cm and splenomegaly. A CT scan of the chest showed extensive mediastinal adenopathy measuring up to 1.3 x 1.4 cm and bilateral axillary lymphadenopathy with the largest lymph node measuring 1.5 x 1.1 cm. Initial blood work showed a lactate dehydrogenase (LDH) level of 634 U/L, white cell count of 7.36 million cells/mcL with a normal differential, hemoglobin of 11.9 g/dL and a platelet count of 276,000/microliter. Coagulation studies and a comprehensive metabolic panel were within normal limits. An excisional biopsy of the right inguinal lymph node was performed, and pathologic exam revealed a biphasic lymphoid population consisting of a large cell population strongly positive for B-cell antigens, CD20 and PAX5, and germinal center cell antigens, CD10 and BCL6. Ki-67 was expressed in 80-90% of the cells. The cell regulatory protein p53 was expressed in the majority of the larger cells, supporting the diagnosis of germinal center-like large B-cell lymphoma. Unexpectedly, the small cell component was also positive for the B-cell antigens, CD20 and PAX 5, with aberrant co-expression of the T-cell antigen CD43 (dim). Distinct nuclear positivity for cyclin D1 (BCL1) was present. BCL2 was also positive, consistent with a diagnosis of mantle cell lymphoma. Epstein-Barr encoding region (EBER) in situ hybridization was negative (Figure (Figure11). Full Text: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5298913/