Extramedullary plasmacytoma of the ureter.

Introduction: We report a rare case of an extramedullary plasmacytoma of the ureter.

Case Presentation: A 77-year-old man was referred to our hospital because of left hydronephrosis. Computed tomography showed a tumor in the left ureter, and tumor invasion into the periureteric fat was suspected. Urine cytology showed Eatypical cells whose nuclei were hyperchromatic (class IIIb). The left ureteral tumor was diagnosed as urothelial carcinoma (cT3N0M0) preoperatively. Subsequently, we performed laparoscopic radical nephroureterectomy with bladder cuff excision. The tumor was pathologically diagnosed as a plasmacytoma. Postoperative positron emission tomography did not reveal abnormal uptake, and bone marrow aspiration findings were normal. Consequently, the left ureter tumor was diagnosed as an extramedullary plasmacytoma of the ureter.

Conclusion: Extramedullary plasmacytoma commonly occurs in the upper respiratory tract or upper gastrointestinal tract. Extramedullary plasmacytoma of the ureter is rare. This is only the fourth reported case of extramedullary plasmacytoma of the ureter.