Undifferentiated Pleomorphic Sarcoma of the Hand with Lung Metastases.

Undifferentiated pleomorphic sarcoma (UPS) is a rare tumor of mesenchymal origin affecting the hand in less than 3% of cases. A 92-year-old male reported an enlarging, painless mass on his left hand of three months duration. Examination of the hand revealed a soft, non-tender, immobile mass over the wrist joint, just proximal to his thumb.