[A case of the primary mediastinal seminoma invading into the extradural space of the thoracic spine].

Seminomatous germ cell tumors can arise as primary mediastinal malignancies in the mediastinum without involving the testis. The usual location is the superior mediastinum and histologically it is identical to the testicular seminoma. Here we report a case of extradural spinal cord tumor by primary mediastinal seminoma. The patient, 24 year old male, was evaluated for complaints of severe back pain associated with dysesthesia in lower limbs. He was operated as primary mediastinal seminoma when he was 21 years old. On admission, physical examination was unremarkable except for hypereflexia in lower extremities. The testis were normal. Chest radiography and computed tomography revealed a large mediastinal mass which invaded into the extradural space of the thoracic spine. He had a laminectomy of the thoracic spine and was treated by the radiation therapy and chemotherapy. This is the first report showing the neuroradiological findings of the extradural spinal cord tumor by primary mediastinal seminoma.