Epstein-Barr virus-positive diffuse large B cell lymphoma arising from a chronic lymphocytic leukemia: Overlapping features with classical Hodgkin lymphoma.

A small proportion of patients with chronic lymphocytic leukemia (CLL) may progress to large cell lymphoma, or Richter syndrome (RS). The large cells of RS may arise through transformation of the original CLL clone (clonally related) or represent a new neoplasm (clonally unrelated), which might be Epstein-Barr virus (EBV)-associated. We present a 61-year-old male with 5-year history of CLL who developed RS on bilateral adrenal glands. The tumor showed a vague nodular growth pattern separated by thick fibrous bands and the tumor cells were large and pleomorphic, with focal sheet-like growth pattern, in a background of small B and T-lymphocytes. The large tumor cells were positive for CD15, CD19, CD20 (intensely and diffusely), CD30, fascin, PAX5, MUM1, OCT2, and LMP-1 by immunohistochemical stains, and EBV by in situ hybridization. The tumor was diagnosed as EBV-positive diffuse large B cell lymphoma (DLBCL), with overlapping features of classic Hodgkin lymphoma (CHL). The patient received salvage chemotherapy and was free of disease 2 years after adrenalectomy. We speculated that our case was a clonally unrelated tumor with his underlying CLL and discussed the differential diagnoses between EBV-positive DLBCL and CHL in the setting of RS.