Hypertension from ipsilateral renin hypersecretion following kidney upper pole compression by the spleen.

A unique case of renovascular hypertension in an asymptomatic, microhematuric 61/2-year-old girl is presented. Abdominal ultrasonographic (UT) and computed tomographic (CT) studies, splenic and renal radionuclide evaluations revealed that a 'boomerang'-shaped spleen, anterior and medial to the left kidney, compressed and flattened its upper pole. Arteriography excluded stenosis of the renal arterial vessels. Renal vein renin ratio of 1.78 and contralateral/caval ratio of 1.13 eventually demonstrated that hypertension was caused by a lateralized renin hypersecretion from the compressed upper pole through left superior and central renal veins. Overactivity of the renin/angiotensin system was presumably due to ischemia of the renal parenchyma extrinsically compressed by the spleen.