Extraskeletal myxoid chondrosarcoma of the perineum.

Extraskeletal myxoid chondrosarcoma is an aggressive tumor with significant metastatic potential. A 40-year-old man presented with an asymptomatic mass at the left ischial fossa. Magnetic resonance imaging showed a 9x6-cm mass with variable signal intensity and cystic formations. A computed tomography scan of the chest showed multiple pulmonary nodules. A computed tomography-guided core needle biopsy was consistent with low-grade extraskeletal myxoid chondrosarcoma. Despite the presence of lung metastases, wide resection of the primary tumor was performed. Wide resection included the perineal mass and the adjacent ischiopubic ramus. Postoperative recovery was uneventful. One month postoperatively, thoracotomy was performed, and approximately 20 pulmonary nodules were excised. Histological analysis of the excised specimens was consistent with extraskeletal myxoid chondrosarcoma metastases. Two years postoperatively, the patient is alive without evidence of local recurrence or distant disease. Extraskeletal myxoid chondrosarcoma is an unusual soft tissue sarcoma with ultrastructural and molecular features distinct from that of skeletal myxoid chondrosarcoma. The EWS-CHN gene fusion is highly specific to extraskeletal myxoid chondrosarcoma; the gene fusion is positive in >or=75% of cases. Treatment should include wide excision for local tumor control. Resection of the lung metastases is feasible. Because of the prolonged survival of patients with extraskeletal myxoid chondrosarcoma, long-term follow-up is recommended for early detection of local recurrence or distant metastases.