RESUMO
Compression of the left renal vein (LRV) between the superior mesenteric artery and the aorta has been termed the nutcracker syndrome. The entrapment of the left renal vein is not easily detectable by ordinary diagnostic procedures. We report 2 cases of the nutcracker syndrome with symptoms ( / ) diagnosed by phlebography and pressure measurement. In both cases, no remarkable findings were obtained from medical history and physical examination. Profuse collaterals from a left renal vein in one case with no symptom were observed in venous phase of renal angiography. In the other case, recurrent left flank pain and microscopic hematuria developed. In both cases, the diagnosis of "nutcracker phenomenon" was presumed by renal venography with measurement of pressure gradient between left renal vein and inferior vena cava. Awareness of the pathophysiology of the nutcracker syndrome ensures an early diagnosis. New diagnostic modalities are demanded for atypical cases.