Saphenous venous cavernous angioma masquerading as an aneurysm

Cavernous angiomas are common in the upper body and viscera but saphenous vein cavernous angiomas have not been previously described in the literature. We present a case of a rare congenital vascular malformation of the lower extremity masquerading as an aneurysm in a 4-year-old girl who presented with an asymptomatic right lower leg mass. Ultrasound was concerning for saphenous venous aneurysm and MRI was confirmatory. Operative exploration identified a vascular mass without evidence of an aneurysm; cavernous angioma was confirmed on pathologic examination. Although infantile vascular lesions are common, imaging diagnosis of venous aneurysm – an unusual asymptomatic clinical entity – should raise concerns about possible rare entities or diagnostic alternatives.