Multiple Myeloma Causing Gastric Polyposis

A 71-year-old white man with Durie-Salmon stage IIIB multiple myeloma diagnosed 1 year prior presented with obstructive jaundice. He had received multiple cycles of chemotherapy. Abdominal computed tomography scan showed a 2.5-cm pancreatic head mass with mild biliary and pancreatic duct dilatation. The patient was scheduled for endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) and endoscopic retrograde cholangiopancreatography for biliary drainage. Endoscopic examination of the stomach revealed multiple large, pedunculated, and sessile polyploid lesions seen diffusely throughout the stomach, some of which were ulcerated (Figure 1). EUS examination of these lesions revealed hypoechoic mucosal and submucosal masses within an isoechoic rim. No communication with the muscularis propria was noted. Biopsies and FNA of the gastric polyps were consistent with plastocytoma (Figure 2). EUS exam of the pancreas showed a 35.6 mm x 27.9 mm hypoechoic and poorly demarcated pancreatic/parapancreatic mass. FNA of this mass was consistent with metastatic multiple myeloma. Biliary drainage was performed using a 10-French x 10 cm plastic biliary stent. Given the overall prognosis and progression of the disease, the patient was referred for hospice care, where he died 2 months later