EBV positive lymphoma with ambiguous lineage: A diagnostic challenge

We describe a case of EBV-positive lymphoma with characterization of histological, immunophenotypic, and molecular features and a brief literature review of similar entities. Atypical large lymphoid cells with pleomorphic nuclei, moderate eosinophilic cytoplasm, and high mitotic activity were noted along with positivity for CD20, OCT2, CD79a, CD19, CD2, perforin, CD30, MUM1, c-MYC, BCL-2, and CD45. Dim positivity with PAX5 and weak cytoplasmic staining with CD3 was noted. These cells were negative for CD4, CD5, CD7, CD8, CD10, BCL-6, CD15, EMA, HHV-8, TdT, Cyclin-D1 and Granzyme B. EBV encoded RNA in situ hybridization was diffusely positive in atypical cells. Both T and B cell gene rearrangements were detected which demonstrates lineage overlap in EBV-positive large cell lymphomas, supported by B and T-cell receptor gamma gene rearrangement proven on molecular studies. The presence of similar entities may lead to potential misclassification of neoplasms. No prognostic significance of this finding was identified.