Duodenal localization of plasmablastic myeloma

Gastrointestinal involvement in plasma cell neoplasms, either as primary localizations (extramedullary plasmacytomas) or as secondary involvement in systemic multiple myeloma, is a well-known event. Accurate histological examination is crucial in defining the diagnosis. In this report, an uncommon case of duodenal localization of myeloma with plasmablastic features is described, with emphasis on the role of clinical data and findings from ancillary immunostaining techniques to avoid misdiagnosis.