Solitary Testicular Plasmacytoma: A Case Report

Introduction: Plasmacytoma of the testis is an extremely rare malignancy that may occur as a solitary tumor, also known as solitary testicular plasmacytoma (STP), or in conjunction with multiple myeloma (MM). Previous studies have shown that STP has a good prognosis and can be cured with localized treatments like radiotherapy or surgery. We report a case of STP with dissemination to the ribs. The patient required systemic chemotherapy. Case Presentation: A 69-year-old man was referred to our hospital due to swelling of the left scrotum. The patient underwent left inguinal high orchiectomy. Based on pathological examination, the specimen was diagnosed as testicular plasmacytoma. As the tests for MM were negative, the patient was followed up. Sixteen months later, multiple bone lesions were detected in the left rims, although serum protein electrophoresis did not show the presence of M protein. Therefore, the patient received 4 courses of chemotherapy, and no signs of recurrence have been detected so far. Conclusion: STP is an extremely rare disease, which obscures its true prognosis. Systemic chemotherapy should be considered for patients with STP in case of recurrence, and long-term follow-up is necessary to understand the nature of the disease.