[ANEURYSMAL TYPE RENAL ARTERIOVENOUS FISTULA WITH GIANT VENOUS ANEURYSM, MIMICKING RENAL CELL CARCINOMA: A CASE REPORT].

A 39-year-old man was referred to our clinic for a 7 cm tumor in the right kidney, found by simple CT scan. It was suspected as renal cell carcinoma accompanying tumor emboli in the inferior vena cava by enhanced CT scan. For further evaluation of the tumor emboli, color Doppler ultrasound and enhanced MRI was performed. They showed a large cystic lesion with high velocity turbulent flow and flow voids in T2-weighted imaging, it seemed as giant venous aneurysm of the right renal vein. Subsequently, angiography revealed aneurysmal type renal arteriovenous fistula (AVF), transarterial embolization (TAE) of the arterial feeder with coils was performed on the same day. After 6 months from embolization, there was no recurrences or reinterventions. Color Doppler ultrasound and MRI are beneficial in distinguishing vascular disease from neoplastic disease which may sometimes mimick in other diagnostic imaging studies. In addition TAE seems to be an effective treatment for the AVF.