Primary mediastinal seminoma

Abstract

We report two cases of seminomatous germ cell tumor originating in the anterior mediastinum. Case 1: A 67-year-old man was referred to our hospital for further evaluation of an abnormal mediastinal shadow identified on a routine chest radiograph. Chest computed tomography (CT) scan revealed a 10.0×8.0×8.0-cm mass in the anterior mediastinum. Surgical resection of the tumor which involved the right upper lobe of the lung was performed with a diagnosis of suspected invasive thymoma. An immunohistopathological examination showed the tumor to be a primary mediastinal seminoma. Postoperative radiotherapy was performed with a total dose of 50 Gy. Nine months after surgery, local recurrence was found, and complete right upper lobectomy of the lung was performed. The patient was treated with two cycles of chemotherapy consisting of cisplatin, etoposide, and bleomycin. He is now disease-free at 7 years and 6 months after the salvage surgery. Case 2: A 25-year-old man visited our hospital for further examination of an abnormal shadow on chest radiograph. CT scan demonstrated a 9.6×8.6×8.5-cm mass in the anterior mediastinum, and CT- guided needle biopsy of the tumor was performed. Immunohistological evaluation of the biopsy specimen showed findings of seminomatous germ cell tumor. The patient received four cycles of systemic chemotherapy with a combination of cisplatin and etoposide, and then underwent surgical resection of the residual tumor. Histopathologically, there was no viable malignant cell in the resected specimen. He is now disease-free at 14 months after surgery, receiving no adjuvant chemotherapy. The standard strategy for the treatment of malignant germ cell tumors is cisplatin-based systemic chemotherapy. Therefore, in cases of suspected malignant germ cell tumors, confirmation of the histological diagnosis is required before initial treatment.