Alveolar soft-part sarcoma of the mediastinum: A case report.

We report a 53-year-old man with metastases of alveolar soft-part sarcoma originated from the mediastinum. He was hospitalized due to lower extremities' paralysis. Computed tomography scan findings revealed multiple nodules of bilateral lungs, swollen mediastinal lymph nodes, and osteolysis of thoracic vertebrae. We performed spinal decompression and biopsy from vertebra. And, we finally diagnosed this case as metastases of mediastinal alveolar soft-part sarcoma which was removed 10 years ago. Alveolar soft-part sarcoma is rare tumor accounted for 0.5%-1.0% of soft tissue sarcoma that often occurs primarily in the lower extremities and trunk. It is difficult to distinguish between alveolar soft-part sarcoma and paraganglioma, renal cell carcinoma and granular cell tumor morphologically. Periodic acid-Schiff stain and immunohistochemical staining of ASPL-TFE3 are useful in making a definitive diagnosis of alveolar soft-part sarcoma. This case is a rare case of alveolar soft-part sarcoma originated in the mediastinum with local recurrence and distant metastases 10 years after the initial surgery.