Plasmablastic myeloma transformation of light-chain multiple myeloma.

Plasmablastic myeloma (PBM) is an uncommon and aggressive morphologic variant of multiple myeloma (MM). The neoplastic immature cells exhibit diverse morphology, posing a diagnostic challenge. The diagnostic criteria for PBM include the identification of ≥ 2% plasmablasts in the bone marrow aspirate. This case describes the incidental finding of a light-chain multiple myeloma (LCMM) transformed into PBM, a phenomenon not previously reported.