Detection of Extramedullary Multiple Myeloma in Liver by FDG-PET/CT

lesion in the right shoulder that was detected by contrastenhanced computed tomography (CT) and F-fluoro-2deoxyglucose (F-FDG) positron emission tomography (PET)/CT (Fig. 1). Excisional biopsy revealed infiltration of plasma cells with anaplastic features, consistent with solitary plasmacytoma (PC). Serum analysis showed elevation of serum free lambda light chain levels (27.78 mg/l), with an abnormally high kappa:lambda ratio (2.33) and high total proteins (10.4 g/dl). Serum protein electrophoresis revealed an M spike in the gamma-globulin region (56.1 %=5.8 g/dl). Subsequently, F-FDG PET/CT revealed another hypermetabolic mass in the right lobe of the liver (Fig. 2). CT-guided biopsy of the liver lesion revealed plasma cell myeloma, consistent with multiple myeloma (Fig. 3). Multiple myeloma presenting as nodular liver masses is very rare in clinical practice. In a retrospective review of more than 2,000 patients, Talamo et al. [1] reported only nine cases where there was nodular involvement of the liver by multiple myeloma. The organ most commonly involved was the liver, followed by pancreas, stomach, peritoneum with malignant ascites, colon, rectum, duodenum and ileum [1]. Therefore, the literature published thus far has been limited to a few reports and case series [2–10]. Among these reports, some had demonstrated the PET or PET/CT findings of nodular liver involvement of multiple myeloma [6, 8–10]. About 10 % of the solitary myelomas appeared as extramedullary PC or solitary PC of bone [11]. In spite of the advances in therapy, the treatment of multiple myeloma is still palliative. However, solitary PC could be cured by resection or radiation therapy [11]. Thus, differentiation between PC and multiple