A CASE OF A RENIN-SECRETING TUMOUR IN AN ADOLESCENT

A RARE YET CURABLE CAUSE OF HYPERTENSION

Abstract

INTRODUCTION
Reninomas are benign tumours of the juxtaglomerular apparatus that autonomously secrete renin. Only 100 cases have been reported in the literature. Adolescents with reninomas typically present with refractory hypertension that requires treatment with multiple anti-hypertensives. However, hypertension secondary to reninomas are curable with surgery. Another, minimally invasive procedure, known as cryoablation has been successfully used to cure hypertension in an adult with reninoma, but this has not been reported in an adolescent.

CASE
We conducted a retrospective chart review of the pertinent clinical, biochemical, radiological and histopathological details. We report on a 14-year-old male with a hypertensive emergency; blood pressure 180/100 mmHg and Bell’s palsy. His initial investigations showed hypokalaemia 2.2 mmol/L, metabolic alkalosis, raised plasma renin activity 2235 mU/L and aldosterone 8056 pmol/L, suggesting a high-renin mineralocorticoid excess syndrome. A right-sided renal cortical cyst was seen on abdominal computed tomography, measuring 0.9 x 1.6 cm. In order to accurately establish lateralisation of the autonomous renin secretion, renal vein sampling (RVS) was conducted to determine renin ratios, which confirmed lateralisation to the right renal vein (ratio 2.72). His hypertension was difficult to control despite amlodipine, prazosin and verapamil and captopril. There were no complications. Following adequate optimisation of his hypertension, he underwent cryoablation of the lesion. The histopathology was conclusive for a juxtaglomerular tumour. One week post ablation, he had resolution of his hypertension and normalisation of the plasma renin activity to 13.4 mU/L after 1 month.

CONCLUSION
Reninoma, though rare, should be considered in adolescents who present with a triad of refractory hypertension, hypokalaemia, and metabolic alkalosis. It is a curable with surgery, but cryoablation should be given due consideration. This case report illustrates that cryoablation can be used successfully for the management of reninoma in adolescents.