Diffuse Large B-Cell Lymphoma with pseudo Rosettes, A Rare Entity: Case Report with Literature Review.

Rosette formation is an unusual finding in malignant lymphomas. We report a case of a diffuse large B-cell lymphoma (DLBCL) with abundant rosette formation histologically mimicking non lymphoid tumors. A sixty-five-year-old female presented with a complaint of swelling on left side axillary region since a period of six months with no history of fever, fatigue or weight loss or other similar swellings elsewhere. No relevant personal and family history relatable to the present complaint. Subsequent clinical and radiological investigations revealed isolated left axillary lymphadenopathy. The lymph node on further biopsy showed a particular morphology of pseudorosette formation masquerading a metastatic rosette forming malignancies. Subsequent histopathological and immunohistochemical investigations revealed a rare morphological variant of diffuse large B cell lymphoma. The fluorodeoxyglucose positron emission tomography scan showed multiple discreet supra-diphramatic (left lower cervical and left axillary lymph nodes) metabolically active lymph nodes. Diffuse large B cell lymphoma with rosette formation is a rare entity which can mimic other tumors with rosette formation in a metastatic node. Knowledge on the rosette forming lymphoma entity is thus essential for diagnosis and treatment plan. To the best of our knowledge this case report is the sixth known documented case of a diffuse large B cell lymphoma with rosette in literature.