A Case of Solitary Extramedullary Plasmacytoma of the Spleen

Abstract

A solitary extramedullary plasmacytoma (EMP) is a rare from of plasmacytoma and is often located in the upper and lower aerodigestive and gastrointestinal tract. We report a rare case involving a solitary EMP that occurred from the spleen. A 76-year-old man with indications of solitary EMP based on routine abdominal ultrasonography was referred to our department from a previous medical department. He did not exhibit any symptoms, and blood test results revealed no increase in tumor markers. Computed tomography revealed a well-defined splenic tumor, 46 mm in diameter. After various examinations, he underwent splenectomy because the possibility of malignant lymphoma could not be discounted. The resected spleen, weighing 130 g, contained a solid mass measuring 52 mm × 40 mm. Histopathologically, the tumor had plasmacystic monoclonal growth. There were no tumors in other organs except the spleen, and on postoperative examination, there was no evidence of bone lesions and urinary Bence Jones protein. Thus, we confirmed the diagnosis of solitary EMP of the spleen. After the surgery, he continues to be followed-up without undergoing additional chemotherapy, and there has been no recurrence 20 months post-surgery.