Renal plasmacytoma: Report of a rare case and review of the literature.

Renal plasmacytoma is extremely rare, presenting diagnostic challenges due to its unusual location and non-specific or absent symptoms. To the best of our knowledge, only 24 cases of renal plasmacytoma have been reported in the literature. The present study reports a case of primary renal plasmacytoma in a 46-year-old female patient. Computed tomography (CT) revealed that the mass was located in the lower pole of the left kidney and metastasis was detected in an enlarged para-aortic lymph node. Following careful preparation, a partial nephrectomy was performed and the retroperitoneal lymph node was resected. A pathological examination revealed a renal parenchyma with lymph node involvement; this was confirmed by immunohistochemistry and nested polymerase chain reaction (PCR). Consequently, a diagnosis of a renal extramedullary plasmacytoma (EMP) was proposed. Following this unexpected diagnosis, various examinations were performed, but there was no evidence of systemic plasma cell disease. The patient refused further therapy, including external beam radiotherapy and chemotherapy. Abdominal CT was performed three months post-surgery and did not reveal any relapse. The patient remains disease-free at nine months post-surgery. The current study also presents a review of the literature. Although the general prognosis and outcome of EMP is good, a follow-up examination is recommended due to the possibility of relapse or progression to plasma cell neoplasm (PCN).