[Solitary Locoregional Metastasis of an Undifferentiated Pleomorphic Sarcoma in the M. quadratus Femoris]

The undifferentiated pleomorphic sarcoma (UPS) is a part of the soft tissue sarcoma group and represents almost 10% of all soft tissue sarcomas. The case of a 49-year-old patient is presented who was diagnosed with a primary UPS in the left gluteus maximus muscle, which was treated with compartmental resection with adjuvant radiotherapy (60 Gy). During tumor follow-up (3 years later) a locoregional metastasis at an unusual location in the quadratus femoris muscle was detected, which was treated by in toto resection with intraoperative radiotherapy (10 Gy). The intra and postoperative outcome was without complications and without neurological deficits. In the last follow-up, 6 months postoperatively, the patient was free of tumors and symptoms.