A Surgical Case of Solitary Extramedullary Plasmacytoma Occurring in the Mediastinum

Background. Extramedullary plasmacytomas are rare neoplasms among plasma cell tumors and occur mainly in the upper respiratory tract or oral cavity. Such tumors limited to the mediastinum are extremely rare. Case. A 65-year-old man consulted our hospital due to a mediastinal tumor revealed on chest X-rays and computed tomography (CT). Bronchoscopic needle biopsy failed to enable a definitive diagnosis. The mediastinal tumor was completely resected. The completely encapsulated tumor was 40×45 mm. Neither trachea nor the great vessels were involved. Histopathological findings revealed plasmacytoma producing a monoclonal IgG kappa component and positive for Cyclin D1 on immunohistochemical staining. At 8 months after surgery, the patient remains well, and there is no evidence of recurrence or development of multiple myeloma. Conclusion. Solitary extramedullary plasmacytoma occurring in the mediastinum is extremely rare. In this paper, we report a surgically treated case of extramedullary plasmacytoma occurring in the mediastinum.