Juxtaglomerular cell tumor: Clinicopathologic evaluation in a large series emphasizing its broad histologic spectrum

Juxtaglomerular Cell Tumor With Cytohistological Correlation: A Case Report

Juxtaglomerular cell tumors (JCT) are uncommon renin-secreting tumors of the kidney with cytologic findings of JCT rarely reported. We describe a case of JCT in a 37-year-old man with uncontrolled hypertension that was cured by removal of the tumor via partial nephrectomy. Cytology material was prepared by scraping of the freshly sectioned tumor mass and stained with Diff-Quik and Papanicolaou stains. Cytohistological findings and immunohistochemistry studies are discussed regarding diagnosis and differential diagnoses.

Unravelling a mystery of hypokalemic hypertension- a rare case report of a reninoma

BACKGROUND

Reninoma is a rare cause of secondary hypertension, which can be cured with surgery if identified early before any target organ damage occurs. It leads to hypokalaemia and hypertension and typically responds well to treatment with renin-angiotensin-aldosterone system blockers. However, confirmation of the diagnosis and the localisation of this rare culprit lesion can be challenging.

CASE PRESENTATION

We describe a case of young-onset hypertension in a 19-year-old girl due to a reninoma. She had resistant hypertension with marked hypokalaemia, which required exceedingly high doses of potassium supplements. Biochemical Investigations revealed secondary hyperaldosteronism. Thus, she underwent a renal angiogram to exclude a renovascular cause for her hypertension. While the renal artery anatomy was normal, there was an exophytic renal lesion in the lower pole of the left kidney. Hence, the diagnosis of a reninoma was suspected. She underwent renal vein sampling to confirm the functionality of the detected tumour, but the results were inconclusive. After a multidisciplinary discussion, based on the clinical evidence, the renal lesion was thought to be a reninoma and a partial nephrectomy was done, removing the lesion. Immediately following resection, her blood pressure and potassium normalised without further drug treatment, and the resected lesion was later confirmed to be a reninoma by histopathological examination.

CONCLUSION

In young people with hypokalemic hypertension, reninoma should be considered when the more common causes are excluded since prompt treatment with excision of the culprit lesion can cure hypertension and prevent associated morbidity and mortality.

A locally infiltrative juxtaglomerular cell tumor with unusual histologic features

Juxtaglomerular cell tumor (JGCT) is an exceptionally rare renal tumor with a predominantly benign clinical course and classically bland histology. It commonly presents in young adults and manifests as hypertension related to renin secretion. We report a JGCT initially thought to be a renal cell carcinoma. It was unique because of its size, high-grade histologic features and locally infiltrative nature-extension into the renal pelvis. It is unclear whether features such as tumor necrosis, pleomorphism and increased proliferative activity are predictive of metastatic potential and/or locally aggressive behavior. Clinical follow-up may be warranted in such cases.

Molecular Characterization of Juxtaglomerular Cell Tumors: Evidence of Alterations in MAPK-RAS Pathway

Juxtaglomerular cell tumor (JGCT) is a rare neoplasm, part of the family of mesenchymal tumors of the kidney. Although the pathophysiological and clinical correlates of JGCT are well known, as these tumors are an important cause of early-onset arterial hypertension refractory to medical treatment, their molecular background is unknown, with only few small studies investigating their karyotype. Herein we describe a multi-institutional cohort of JGCTs diagnosed by experienced genitourinary pathologists, evaluating clinical presentation and outcome, morphologic diversity, and, importantly, the molecular features. Ten JGCTs were collected from 9 institutions, studied by immunohistochemistry, and submitted to whole exome sequencing. Our findings highlight the morphologic heterogeneity of JGCT, which can mimic several kidney tumor entities. Three cases showed concerning histologic features, but the patient course was unremarkable, which suggests that morphologic evaluation alone cannot reliably predict the clinical behavior. Gain-of-function variants in RAS GTPases were detected in JGCTs, with no evidence of additional recurrent genomic alterations. In conclusion, we present the largest series of JGCT characterized by whole exome sequencing, highlighting the putative role of the MAPK-RAS pathway.

Clinical features, laboratory findings and treatment of juxtaglomerular cell tumors: a systemic review

Juxtaglomerular cell tumors (JGCTs) or reninoma are rare kidney tumors leading to secondary hypertension, and the non-specific clinical manifestations bring about challenges to the diagnosis. This study is to summarize the clinical features, laboratory findings, and treatment of JGCTs. The PubMed, EMBASE database, and manual search were utilized to find all cases, and 158 reports containing 261 patients were identified. Data on patients' demographics, clinical features, diagnostic methods, and treatment options were collected and analyzed. JGCTs occurred predominantly in female patients (female to male ratio, 2.1:1). The median age of patients was 25 years (IQR:18-34 years). Hypertension (97.24%) was the cardinal manifestation. Hypokalemia was reported in 78.71% (159/202) of subjects, and normal serum potassium accounted for 20.79% (42/202). In cases with assessed plasma renin activity (PRA) levels, the median PRA was 7.89 times the upper limit of normal (IQR:3.58-14.41), and 3.82% (5/131) of cases in the normal range. Tumors were detected in 97.8% (175/179) computed tomography (CT), 94.7% (72/76) magnetic resonance imaging (MRI), and 81.5% (110/135) ultrasound, respectively. For 250/261 patients undergoing surgical procedures, 89.14% (197/221), 94.94% (150/158), and 100% (131/131) of patients were restored to normal blood pressure, PRA, and serum potassium, respectively. JGCTs are commonly associated with hypertension, hypokalemia, and hyperreninemia, whereas patients with normotension, normokalemia, and PRA should be systematically pursued after drug-elution lasting for 2 weeks. CT and MRI are more sensitive imaging diagnostic methods. The blood pressure and biochemical parameters of most patients returned to normal after surgery.

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.