Gastroduodenal Plasmacytoma Presenting with Jaundice

The duodenum and gastrointestinal tract are rarely involved by multiple myeloma, either diffusely or as a focal mass. A 59-year-old man was diagnosed with multiple myeloma and given chemotherapy. Four months later, he developed jaundice. Gastroduodenal plasmacytoma causing extrahepatic biliary obstruction was diagnosed. To the best of our knowledge, this case is the first report of gastroduodenal plasmacytoma presenting with biliary obstruction.