Reninoma: The Importance of Renal Vein Renin Ratios for Lateralisation and Diagnosis

Abstract

Background/Aim: Reninomas are rare juxtaglomerular tumours which can cause severe hypertension and hypokalaemia. Diagnosis can be problematic and these tumours can be difficult to locate on imaging. In this report we aim to demonstrate the value of carefully performed renal vein renin ratios (RVRRs) to assist in locating these tumours. Method/Results: We report on 3 patients diagnosed with reninoma in our unit. The patients were all female, young (17, 16 and 30 years), severely hypertensive and hypokalaemic (2.5, 2.5 and 3.1 mmol/l). Plasma renin activity (PRA) was elevated (31.9, 274 and 175 ng/ml/h), and aldosterone was high-normal (19.9 ng/dl) or elevated (207 and 109.3 ng/dl). Renal artery stenosis was excluded by renal artery Doppler, DTPA scan and angiography. Renal CT detected the lesion in 2 patients, with one lesion visible on pre- and post-contrast CT and the other on post-contrast CT only. RVRRs were performed several weeks after withdrawing interfering medications, maintaining a <40 mmol/day low-sodium diet and maintaining recumbency overnight the night before and during the procedure. Ratios before and after captopril or enalaprilat administration were obtained and lateralised the tumours in all 3 cases (dominant/non-dominant ratios of 2.3, 4.3 and 3.8). All of the patients underwent nephrectomy yielding a typical juxtaglomerular tumour and resulting in cure of hypertension and hypokalaemia. Conclusions: Reninoma should be suspected in young hypertensives (especially females) with significant hypokalaemia and high PRA or direct renin concentration after renovascular hypertension has been excluded. CT imaging and carefully performed RVRRs provide the highest likelihood of locating these tumours.

Spontaneous rupture of the kidney in the patients with synchronous renal hemangioma and nephrogenic hypertension

“…[6] Juxtaglomerular cell tumor is the best known neoplasia that causes secondary hypertension. [7] Therefore, from the clinical perspective, hemangiomas causing hypertension can be mistakenly evaluated as juxtaglomerular cell tumours. In addition, it has been reported that lesions such as intrarenal neuroblastoma, diffuse renal lymphangiomatosis, renal lymphatic malformation, multicystic nephroma induce secondary hypertension.…”

Advantages of renin inhibition in a patient with reninoma

“…A selective renal vein sampling was performed in order to evaluate the production of renin from both kidneys. PRA was increased in the blood refluent from renal veins on both sides (21.5 ng/ml/h in the right renal vein and N50 ng/ml/h in the left renal vein), with a PRA lateralization on the left side (lateralizing ratio N 2.3) [2].…”

“…A selective renal vein sampling was performed in order to evaluate the production of renin from both kidneys. PRA was increased in the blood refluent from renal veins on both sides (21.5 ng/ml/h in the right renal vein and N50 ng/ml/h in the left renal vein), with a PRA lateralization on the left side (lateralizing ratio N 2.3) [2].The surgical removal of the tumor with partial nephrectomy was proposed, but the surgical team refused to proceed because the left kidney lesion at MRI was interpreted as a renal scar, possibly secondary to a previous pyelonephritis.The patient continued treatment with a calcium antagonist, a betablocker and oral potassium supplements, with satisfactory control of blood pressure and serum potassium levels. She was admitted 2 years later at age 43 because of a transient loss of consciousness, complaining of fatigue, polyuria, nocturia and thirst.…”

“…Reninoma is usually a benign tumor, and only in few cases a malignant behavior was observed [5][6][7][8]. Typically JGC neoplasm presents with a clinical triad of hypertension, hypokalemia and secondary hyperaldosteronism [2,9]. Hypertensive end-organ damage is common [4].…”

Reninoma Presenting in Pregnancy

“…Given the tumor's preponderance in young females (1,2), this is surprisingly only the fifth report describing pregnancy outcome in a patient with reninoma (2-6). Three of four previous reports showed poor outcomes including preterm labor and an intrauterine fetal demise.…”