Positron Emission Tomography With Computed Tomography-Based Diagnosis of Massive Extramedullary Progression in a Patient With High-Risk Multiple Myeloma

Extramedullary disease (EMD) is an uncommon manifestation of multiple myeloma (MM). The incidence ranges from 2% to 20%, with higher frequency in later phases of the disease. Positron emission tomography with computed tomography (PET/CT) proved to be accurate in the detection of EMD. We report here on a massive EMD progression of MM in an elderly patient with cytogenetically high-risk disease that was treated up-front with novel agents. The extramedullary spread was huge, involving both common and atypical sites. The diagnosis of EMD was based on findings of PET/CT at the time of biochemical relapse, before the progression of MM became clinically evident. Considering PET/CT results in the restaging of MM patients at relapse may help to possibly detect, as in the present case, unsuspected and uncommon sites of EMD. This finding might ultimately affect prognosis and therapeutic decisions. Early and prompt diagnosis of EMD by novel imaging techniques, such as PET/CT, may be the first step toward improved management of patients with this rare manifestation of MM.