Acquired peripheral arteriovenous malformations in patients with venous thrombosis: report of two cases.

The etiology of arteriovenous (AV) malformations remains incompletely understood. Two cases of acquired AV malformations wholly located within the thrombosed lumen of the femoral and external iliac veins are presented here. The patients presented with symptoms of high venous pressure: pigmented skin and chronic pain. Such AV malformations have been rarely described in the extracranial circulation. The associated pain was successfully treated with catheter-based embolization of the lesions. The induction of the AV malformations in the peripheral circulatory system raises questions regarding the nature of angiogenesis and its possible triggers.