HISTORYPatient transferred from the country after failed incision and drainage for presumed abscess that had been growing for a few days. Little further information was available from the patient.
There is a 10 x 13 cm vascular mass in the leg which demonstrates slowly swirling spontaneous echo contrast. Color Doppler demonstrates the moving blood. Blood is seen to enter the mass from the superficial femoral artery and there is high velocity flow in the femoral vein suggesting an arterio-venous fistula.
The ultrasound findings were confirmed by a CT angiogram and the lesion treated by stenting the femoral artery. It is fortunate that the initial incision and drainage did not pierce deep enough into the mass. The advantages of ultrasound prior to procedures includes preventing unsuccessful procedures (e.g. failed attempts at abdominocentesis due to absence of ascites) as well as preventing inadvertent incision of vascular masses (such as false aneurysms in intravenous drug users).
Adrian Goudie and James Rippey