Involvement of the uterus by myeloma is an extremely rare manifestation of extramedullary multiple myeloma (MM), denoting a poor prognosis. Extramedullary MM occurs in 7% to 18% of newly diagnosed patients with MM, and 6% to 20% of patients can develop it later. We present a case of extramedullary MM of the uterus suspected on F-FDG PET/CT as a site of disease recurrence in a 47-year-old woman previously in remission. Further evaluation with pelvic MRI identified an infiltrative process involving the uterus, and subsequent tissue sampling confirmed malignant plasma cell infiltration of the uterus. This case highlights a rare site of myeloma recurrence, which can be detected by F-FDG PET/CT.