Testicular aggressive B-cell lymphoma with plasmablastic morphology harboring concurrent IGH::MYC and IGH::BCL2 rearrangements.

BACKGROUND

Aggressive B-cell lymphomas with plasmablastic morphology are uncommon neoplasms that may exhibit overlapping morphologic, immunophenotypic, and genetic features of plasmablastic lymphoma (PBL) and double-hit lymphoma (DHL). Concurrent IGH::MYC and IGH::BCL2 rearrangements are rarely encountered in this setting, particularly in the testis. Here, we describe an unusual case presenting significant diagnostic challenges at the interface between PBL and DHL.

CASE PRESENTATION: We report a 66-year-old, immunocompetent man presenting with a 5 cm left testicular mass. Histologic examination revealed diffuse proliferation of large atypical lymphoid cells with plasmablastic morphology. Immunohistochemically, the tumor expressed CD138, CD38, and MUM1, with focal BCL2, c-MYC protein, and CD79a positivity, while CD20, CD19, PAX5, CD10, BCL6, and ALK were negative. EBV-encoded RNA in situ hybridization was negative. Fluorescence in situ hybridization identified IGH::MYC [t(8;14)] rearrangement in 45% and IGH::BCL2 [t(14;18)] rearrangement in 21% of analyzed nuclei. Next-generation sequencing additionally revealed BRAF V600E mutation, CDKN2A deletion, and human leukocyte antigen class I genomic alterations.

CONCLUSION

This case highlights a rare testicular aggressive B-cell lymphoma with plasmablastic morphology and concurrent IGH::MYC and IGH::BCL2 rearrangements, representing a diagnostically challenging neoplasm at the interface between PBL and DHL. Our findings underscore the value of integrated morphologic, immunophenotypic, cytogenetic, and molecular analyses in evaluating aggressive B-cell lymphomas with plasmablastic features arising in immune-privileged sites.