18 F-FDG PET/CT Findings in a Case of Plasmablastic Myeloma: A Rare Entity.

Plasmablastic myeloma (PBM) is an extremely rare variant of multiple myeloma, having morphologic, clinical, and radiologic overlap with plasmablastic lymphoma (PBL). Thus, distinguishing both becomes vital due to different treatment strategies. Due to limited literature on imaging findings in this rare entity, here we present a unique case of PBM developing in the setting of chronic light chain myeloma, with extensive extramedullary involvement and severe osteopenia, in addition to pleural deposits, pleural effusion, and perinephric fascial deposit. Thus, 18F-FDG PET/CT can be utilized as an important tool in distinguishing PBM and PBL on imaging, assessing disease extent, and identifying critical lesions requiring immediate intervention.