JUXTAGLOMERULAR CELL CAUSE OF SECONDARY HYPERTENSION IN AN ADOLESCENT

Renovascular hypertension following by juxtaglomerular cell tumor: a challenging case with 12-year history of resistant hypertension and hypokalemia

BACKGROUND

Adolescents with secondary hyperaldosteronism often present with severe and treatment-resistant hypertension, along with hypokalemia. Renovascular hypertension is frequently caused by renal artery stenosis, primarily due to atherosclerosis and fibromuscular dysplasia (FMD). The presence of an accessory renal artery (ARA) is a common anatomical variation that can contribute to secondary renal vascular hypertension. However, FMD occurring in the ARA is a rare cause of renal vascular hypertension. Juxtaglomerular cell tumor (JGCT) represents a rare etiology of renal hypertension. The co-occurrence of the pathogenic ARA with JGCT is infrequently reported in the existing literature.

CASE PRESENTATIONS

This case study presents a young individual with a 12-year history of resistant hypertension, initially diagnosed with pathogenic ARA but later confirmed as JGCT 4 years later. Following surgery for JGCT, the patient experienced only temporary stabilization of blood pressure without anti-hypertensive medication. Stenosis of the ARA was definitively diagnosed one and a half years post-surgery, with FMD occurring on the ARA strongly suspected. The patient underwent balloon dilatation angioplasty 3 years later, leading to sustained blood pressure stability with the use of two medications.

CONCLUSIONS

The case study discussed herein involves a patient with resistant hypertension initially diagnosed with ARA but later determined to have late-onset JGCT and renal artery stenosis. It is imperative to consider atypical JGCT in young patients exhibiting resistant hypertension, hypokalemia, and hyperreninemia. Adequate management of renal artery stenosis is crucial in the management of hyperreninemic hypertension.

How to identify juxtaglomerular cell tumor by ultrasound: a case series and review of the literature

PURPOSE

To study the value of ultrasound in the diagnosis of juxtaglomerular cell tumor (JGCT).

METHODS

From January 2005 to July 2020, fifteen patients diagnosed as JGCT by surgical pathology in Peking Union Medical College Hospital were collected. All patients underwent preoperative ultrasound examination. The clinical, laboratory, ultrasound, computed tomography (CT), surgical, and pathological features of the patients were analyzed retrospectively.

RESULTS

The 15 patients were 5 males and 10 females with a median age of 29 years (10∼72 years). 14 of them had hypertension and one had normal blood pressure. The tumors were all solitary, with a median diameter of 1.5 cm (0.9-5.9 cm). Among the fifteen patients, eleven were correctly detected by preoperative ultrasound, and four were missed. There was a significant difference in tumor size (2.64 ± 1.48 cm vs. 1.23 ± 0.21 cm) and whether the tumor protruded outward (9/11 vs. 0/4) between the ultrasound-detected group and the ultrasound-missed group (p = 0.010, p = 0.011). Of the 11 tumors detected by ultrasound, four were extremely hypoechoic, two were hypoechoic, three were isoechoic, and two were hyperechoic. Color Doppler showed no blood flow in five tumors with the size range from 0.9 to 2.0 cm, and mild blood flow in six tumors with the size range from 2.8 to 5.9 cm.

CONCLUSIONS

JGCT is rare, and has characteristic clinical manifestations. Diagnosis should be suspected in case of secondary hypertension, particularly in young women, if no renal vascular cause was found. Ultrasound, combined with clinical manifestations, was helpful for the diagnosis.

Approach to the Patient: Reninoma

A reninoma is a functional tumor of afferent arteriolar juxtaglomerular cells that secretes the enzyme renin, leading to hyperactivation of the renin-angiotensin-aldosterone system. Reninoma is a potentially curable cause of pathological secondary hyperaldosteronism that results in often severe hypertension and hypokalemia. The lack of suppression of plasma renin contrasts sharply with the much more common primary aldosteronism, but diagnosis is often prompted by screening for that condition. The major differential diagnosis of reninoma is renovascular hypertension. Fewer than 200 cases of reninoma have been described. Reninomas have been reported across a broad demographic but have a 2:1 predilection for women, often of childbearing age. Aldosterone receptor blockade, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers offer effective medical management but are contraindicated in pregnancy, so surgical curative resection is ideal. The current optimal imaging and biochemical workup of reninoma and management approach (ideally, tumor excision with subtotal renal resection) are described.