Incidental finding during venous duplex examination: Solitary fibrous tumor or arteriovenous malformation in the left lower extremity

Purpose. - Superficial varicosities surrounding a palpable mass in the posterior aspect of the left thigh were investigated during a venous duplex examination. A well-defined mass with arterial and venous feeding branches strongly suggested the presence of an arteriovenous malformation. We present an unusual case of a soft-tissue thigh mass that appeared to be an arteriovenous malformation by ultrasound and arteriography but after surgical resection was confirmed to be a benign soft tissue tumor. Case Report. - A 32-year old woman presented with superficial varicosities surrounding a painful mass on the posterior aspect of her left thigh. Venous duplex exam demonstrated normal findings of the deep veins, but further investigation of the superficial varicosities revealed a 3.5-cm x 6.0-cm soft-homogenous mass with a large complex network of arterial and venous feeding branches. Arteriography confirmed a well-defined thigh mass with an arterial network feeding the mass. Surgical resection of this well-circumscribed mass was performed. Histological tissue exam revealed a benign low-grade spindle cell neoplasm with blood vessels. Conclusion. - This report highlights the importance of evaluating all abnormal superficial varicosities and palpable soft-tissue masses as part of a lower extremity vascular duplex evaluation because incidental findings not diagnosed through clinical examination may be detected.