Leiomyosarcomas of vascular origin are uncommon. Originated from the smooth muscles of tunica media of major blood vessels leiomyosarcoma of venous origin is 5 times more common than those of arterial origin, 50% of cases originated in the lower vena cava. Most cases are presented in women with a median age of 50 years. We reported a 65-year-old woman, onset of symptoms 3 months before diagnosis with: pain, palpable tumor (9 cm × 5 cm), edema of the left lower extremity and unilateral intermittent claudication. CT with a vascularized mass, unrelated to adjacent muscle (tibialis posterior) of the left lower pelvic member, it displaces the path of the neurovascular bundle, with a probable origin in the posterior tibial vein. Total tumor resection was performed. Pathology reports a high-grade vascular leiomyosarcoma. T2a, Nx, Mx. Stage IIc. The diagnosis was confirmed by immunohistochemistry. The patient had adequate postoperative recovery without complications. Later the patient received 37 cycles of post-operatory radiotherapy. Currently (July 2015) the patient is asymptomatic. We present this case because although the frequency of this type of tumor is low, should be considered as a differential diagnosis in patients with mass, claudication and pain in lower pelvic member.