A Rare Extramedullary Involvement Site in Patients With Multiple Myeloma: Stomach.

Multiple myeloma (MM) is a hematologic malignancy associated with uncontrolled clonal proliferation of plasma cells. Extramedullary disease in MM is an aggressive entity with a poor prognosis. Moreover, involvement of the gastrointestinal tract is a rare aggressive biological sign. 18 F-FDG PET/CT is an irreplaceable modality in the assessment of extramedullary disease. We present 2 cases with gastric involvement of MM that were shown by 18 F-FDG PET/CT and confirmed as plasma cell infiltration pathologically. 18 F-FDG PET/CT studies of MM patients should be interpreted carefully for gastrointestinal involvement, and it should be kept in mind that it can mimic other malignancies.