A thirty-year-old-man was admitted due to visual loss from malignant hypertension. Hypokalemia and urinary potassium loss were found. Plasma renin activity (PRA) and aldosterone were investigated and found to be elevated compatible with secondary hyperaldosteronism. A computed tomography of the abdomen showed a 11.7 x 11.3 x 12 cm ill-defined, nonhomogeneous mass at the middle part of right kidney. The preoperative diagnosis was renal cell carcinoma and the patient underwent right radical nephrectomy. Following nephrectomy, plasma PRA and plasma aldosterone levels declined and serum potassium level returned to normal. A reninoma is a rare benign renal neoplasm arising from juxtaglomerular apparatus. The tumor produces an excessive amount of renin resulting in secondary hyperaldosteronism, thereby causing hypertension with hypokalemia. The authors describe a case of reninoma in a young man, who presented with malignant hypertension and the largest reninoma ever reported.

Keywords: Reninoma, Malignant hypertension, Hyperaldosteronism