Reninoma treated with nephron-sparing surgery.

A 14-year-old hypertensive boy was evaluated in our clinic. The physical examination was essentially normal except for his high blood pressure. Laboratory findings showed increased plasma renin activity. Abdominal ultrasonography detected a hypoechoic, 2-cm mass in right kidney. Contrast-enhanced computed tomography of the abdomen revealed a well-circumscribed, solid, hypoenhancing cortical lesion in the middle of the right kidney. Magnetic resonance angiography documented bilateral normal renal arteries. With a preoperative diagnosis of reninoma, the patient underwent nephron-sparing surgery. Intraoperative frozen section analysis revealed a benign lesion. Subsequently, histopathologic examination and electron microscopy confirmed the diagnosis of juxtaglomerular cell tumor. The patient remained normotensive in the postoperative period. Follow-up intravenous urography showed bilateral normally functioning kidneys.