A malignant lymphoma with histological features and immunophenotypic profile intermediate between EBV-positive diffuse large B-cell lymphoma and EBV-positive classical Hodgkin lymphoma in a 67-year-old female: a "gray zone" lymphoma associated with Epstein-Barr virus in the elderly.

Epstein-Barr virus (EBV) can be associated with both classical Hodgkin lymphoma (cHL) and non-Hodgkin lymphoma of the B-cell type, particularly in immunodeficient patients or elderly individuals. While polymorphic variants of EBV-positive large B-cell lymphoma (EBV+ DLBCL) frequently resemble cHL in morphology, and thereby may cause diagnostic difficulty, a true gray zone lymphoma with overlapping morphological and immunophenotypical features of EBV+ DLBCL and EBV+ cHL has not been reported in the literature. We describe a unique case of an EBV+ malignant lymphoma of B-cell origin with hybrid features of EBV+ DLBCL and EBV+ cHL in a 67-year-old female without an identifiable etiology for immunodeficiency. The biopsy of an enlarged lymph node showed a polymorphic infiltrate containing Reed-Sternberg-like pleomorphic large cells, which were positive for CD30 and CD15. Although CD20 was negative and PAX5 and CD45 were down-regulated, the pleomorphic large cells expressed multiple other B-cell antigens which are characteristically absent in cHL. EBV-encoded RNA hybridization (EBER) studies demonstrated nuclear reactivity in the large cells as well as in the smaller bystander cells. A clonal rearrangement of the immunoglobulin heavy chain gene was also detected by PCR. Although the results of the EBV and genotypic studies suggest this case may be an example of EBV+ DLBCL of the elderly instead of EBV+ cHL, the immunophenotype is strikingly ambiguous. Thus, this case may represent an interface between EBV+ DLBCL and EBV+ cHL.