A Surgical Case of Extramedullary Plasmacytoma in the Anterior Mediastinum

Background. Few cases of extramedullary plasmacytoma occurring in the mediastinum have been reported. Due to the lack of standard therapy, extramedullary plasmacytomas are considered difficult to treat. We herein report a surgical case of extramedullary plasmacytoma in the anterior mediastinum with a review of the literature. Case. A 77-year-old male under treatment for hypertension and prostate cancer was referred to our hospital due to an abnormal chest radiograph. Chest radiography performed on admission to our hospital showed a half-round tumor shadow with a uniform area of concentration projecting from the mediastinum into the right upper lung field. Computed tomography revealed that the tumor was located in front of the superior vena cava, although no vascular invasion was detected on magnetic resonance imaging. Based on these findings, we diagnosed the patient with thymoma and performed video-assisted thoracoscopic tumor resection and thymectomy (partial thymectomy of the right lobe). The pathological findings showed proliferation of atypical plasma cells positive for IgG and λ and negative for IgA, IgM and κ. Therefore, we diagnosed the patient with extramedullary plasmacytoma in the mediastinum. A diagnosis of multiple myeloma was excluded. Conclusions. We herein reported a very rare case of extramedullary plasmacytoma occurring in the anterior mediastinum.