An extremely rare case of anterior mediastinal leiomyosarcoma: a case report.

We herein report an extremely rare case of leiomyosarcoma found in the anterior mediastinum. A 79-year-old man presented to our hospital with an anterior mediastinal mass incidentally found by chest computed tomography (CT) scan. Percutaneous needle biopsy revealed the presence of an undifferentiated sarcoma. Transsternal resection of the tumor with adjacent left mediastinal pleura was performed, and pathological analysis revealed a leiomyosarcoma, which was 11 cm in diameter, with bare margins. He was followed up on an outpatient basis with no adjuvant therapy. Although mediastinal lymph node recurrence was suspected on chest CT scan 18 months after surgery, the patient remained asymptomatic and rejected any additional antitumor treatments. He died of respiratory failure after incidental traumatic spinal injury about 30 months after tumor resection.