Primary undifferentiated pleomorphic sarcoma of biceps femoris

Malignant fibrous histiocytoma-currently known as undifferentiated pleomorphic sarcoma-is the most common soft tissue sarcoma of mesenchymal origin. Undifferentiated pleomorphic sarcoma is commonly located in the extremities, trunk, head, and neck in decreasing order of frequency. We report a case of primary undifferentiated pleomorphic sarcoma of the biceps femoris muscle in a 50-year-old man complicated by hemorrhage. Diagnostic workup included imaging, histopathology, and positive results on immunohistochemistry, especially CD68. High-grade liposarcoma and rhabdomyosarcoma were regarded as differential diagnosis of undifferentiated pleomorphic sarcoma. Demonstration of spontaneous hemorrhage within the lesion on follow-up ultrasonography done at one month from the time of diagnosis deserves special mention in this report. Radical excision with tumor-free margins of the biceps femoris and tendon reconstruction were undertaken. MRI at six-month follow-up did not reveal tumor recurrence at the site of surgery and CT chest did not reveal metastases.