Primary extramedullary plasmacytoma of the kidney: a case report and literature review.

Primary extramedullary plasmacytoma (EMP) of the kidney is a rare indolent lymphoma characterized by the monoclonal proliferation of plasma cells outside the bone marrow. Owing to its special site of origin, it is highly prone to misdiagnosis in clinical practice. Herein, we report a case of primary extramedullary plasmacytoma of the kidney. Abdominal computed tomography (CT) of the patient revealed a left renal mass, and renal carcinoma was considered. After adequate preoperative preparation, the patient underwent a radical nephrectomy for renal carcinoma. Pathological and immunohistochemical results strongly suggested the diagnosis of renal plasmacytoma. Subsequently, the patient underwent various examinations; however, no evidence of systemic plasma cell disease was found. After the surgery, the patient refused further radiotherapy or chemotherapy. Abdominal CT was performed three months postoperatively, and no recurrence was detected. We reviewed the current case, together with previous similar reports, to further understand the characteristics, diagnosis, and treatment of this disease. Although the prognosis of EMP is relatively favorable, regular follow-up examinations are necessary because of the potential risk of recurrence or progression to plasma cell neoplasms.