This is the eighth case of primary reninism so far reported, but it is unusual in that the patient was very young (10 years of age) and the tumor was very small (0.2×0.15 cm), without delineation, yet cure was effected quickly (in five months). The boy, first admitted with malignant hypertension, was thought to have a juxtaglomerular (JG) cell tumor because of typical findings for it: hypertension, hypokalemia, hyperaldosteronism, and unilaterally (right) elevated renal vein plasma renin activity (PRA), with no disparity or abnormality on nephrogram or renal angiogram. Right nephrectomy resulted in a prompt cure and return of PRA to normal levels, but no delineated tumor was found in the excised right kidney. Reexamination showed an extremely small (0.2×0.15 cm) circumscribed nodular lesion in the cortex, which consisted of a group of peculiar cells whose characteristics coincided with neither hemangiopericytoma nor Wilms tumor. Several explanations are possible for the histological findings.
(JAMA 230:1288-1292, 1974)