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.

Juxtaglomerular cell tumor (JGCT) is a rare renal tumor with a predominantly benign clinical course. It affects young adults, who often present with hypertension, hypokalemia, and hyperaldosteronism. The tumor cells are round to spindle-shaped with occasional mild to moderate atypia, but mitotic figures are usually absent. Surgical resection is the treatment of choice. Typically, the blood pressure and renin levels normalize after removal of the tumor. Rare cases of metastatic and recurrent JGCT have been reported including cases with vascular invasion. These cases typically occur in older adults and present with larger tumor size (9-15 cm). We report a case of JGCT, 5.5 cm in greatest dimension, with atypical pathological features including invasion of the renal vein, lymphovascular invasion, and significant pleomorphism with rhabdoid morphology, along with a brief review of the literature.

Juxtaglomerular cell tumors (JCTs), a rare but potentially curable cause of hypertension, are difficult to diagnose because they may be missed or misidentified as a cyst by computed tomography (CT). Their magnetic resonance imaging (MRI) pattern has not been well described. We report the clinical, biological, and radiologic features of 10 patients with JCTs. Eight were women, and median age was 24.5 years. All had severe hypokalemic hypertension related to marked secondary hyperaldosteronism. Median plasma renin and aldosterone concentrations were 392 (minimum-maximum [min-max], 70.5-4,800) mIU/L and 1,490 (min-max, 671-2,492) pmol/L, respectively. Plasma prorenin concentration was 835.5 (min-max, 133-6,546) mIU/L. Median tumor size was 17.5mm. On CT, JCTs were spontaneously isodense, with little enhancement after contrast media injection. On MRI, JCTs were iso- (7/10) or hypointense (3/10) on T1-weighted images (WIs). On T2-WIs, JCTs were hypointense (2/10), isointense (4/10), or heterogeneously hyperintense (4/10). A thin peripheral \"pseudo-capsule\" (hypointense on T2-WIs) was observed in 6 of 10 cases. Contrast enhancement was low, slightly heterogeneous, and delayed. On diffusion-WIs, tumors were hyperintense with a restricted apparent diffusion coefficient. When hypertension with secondary hyperaldosteronism remains unexplained after CT, MRI of the kidney should be considered, especially for young women.

Juxtaglomerular cell tumor (JGCT) generally affects adolescents and young adults. The patients experience symptoms related to hypertension and hypokalemia due to renin-secretion by the tumor. Grossly, the tumor is well circumscribed with fibrous capsule and the cut surface shows yellow or gray-tan color with frequent hemorrhage. Histologically, the tumor is composed of monotonous polygonal cells with entrapped normal tubules. Immunohistochemically, tumor cells exhibit a positive reactivity for renin, vimentin and CD34. Ultrastructurally, neoplastic cells contain rhomboid-shaped renin protogranules. Genetically, losses of chromosomes 9 and 11 were frequently observed. Clinically, the majority of tumors showed a benign course, but rare tumors with vascular invasion or metastasis were reported. JGCT is a curable cause of hypertensive disease if it is discovered early and surgically removed, but may cause a fatal outcome usually by a cerebrovascular attack or may cause fetal demise in pregnancy. Additionally, pathologists and urologists need to recognize that this neoplasm in most cases pursues a benign course, but aggressive forms may develop in some cases.

This report presents a case of a 16-year-old hypertensive boy who presented to our clinic. Laboratory findings showed severe hypokalemia and markedly increased plasma renin activity. Abdominal ultrasonography and contrast-enhanced computed tomography of the abdomen revealed a well-circumscribed, solid, hypoenhancing cortical lesion (2 cm) in the lower pole of the left kidney. The patient underwent nephron-sparing surgery. Histopathologic examination gave a diagnosis of juxtaglomerular cell tumor. Reninoma is an uncommon cause of hypertension in a young adult and should be included in the differential diagnosis as a potential life-threatening and curable condition. The conservative surgical management is the gold standard for small, circumscribed lesions.

Reninoma is a tumor of the renal juxtaglomerular cell apparatus that causes hypertension and hypokalemia via hypersecretion of renin. We describe a case of reninoma and provide a review of the literature, with a discussion emphasizing the diagnostic evaluation for such patients. The subject had persistent elevation of both plasma renin activity (PRA) and aldosterone. Imaging studies revealed the presence of a lesion in the renal cortex, which was further identified as a renin-producing lesion via selective venous catheterization following administration of an angiotensin-converting enzyme inhibitor (ACE-I). Following partial nephrectomy, the PRA and plasma aldosterone levels declined rapidly and the blood pressure and potassium supplementation requirements normalized. This case demonstrates the utility of both appropriate imaging studies and selective venous catheterization following provocative administration of an ACE-I for diagnosis.

We studied 4 new cases of juxtaglomerular cell tumor and compared their morphologic and immunohistochemicalfeatures with 2 renal hemangiopericytomas and 5 cutaneous glomus tumors. The juxtaglomerular tumors were resectedfrom 2 males and 2 females (mean age at diagnosis, 23 years). Three patients manifested with severe hypertension. Tumors ranged from 2.2 to 8.0 cm and were well circumscribed. The tumors consisted of solid sheets and nodules of variably sized tumor cells with round, oval, and spindled nuclei alternating with edematous microcystic foci. Nuclear atypia, present in all tumors, was a prominent feature in 2. Mitotic activity was not identified. All cases showed hemorrhage, numerous mast cells, and thick-walled blood vessels. Unusual features included coagulative tumor necrosis, a hemangiopericytoma-like vascular pattern, and hyalinized stroma. All tumors were immunoreactive for CD34 and actin. Ultrastructural analysis revealed the presence of rhomboid-shaped renin protogranules. Patients were treated by partial or radical nephrectomy and followed up for 14 to 48 months. There were no recurrences or metastases. The characteristic clinical and morphologic features of juxtaglomerular cell tumor permit distinction from renal hemangiopericytoma and other renal tumors.

Bartter\'s syndrome is a rare autosomal recessive disorder characterized by hypokalemia, hyperaldosteronism, sodium wasting, normal blood pressure, hypochloremic alkalosis, and hyperplasia of the juxtaglomerular apparatus. We present a 21-year-old African-American nulliparous patient who was referred to our clinic at 9 weeks\' gestation with a history of Bartter\'s syndrome. Her antenatal course was complicated by muscle cramps, which required increasing potassium supplementation. She developed hypomagnesemia in the third trimester of pregnancy, which necessitated magnesium therapy. She delivered an unaffected infant at term. Bartter\'s syndrome, although extremely rare in pregnancy, requires prompt recognition and careful management, as it may have significant maternal and neonatal implications.

A 15-year-old girl with severe high renin hypertension caused by a juxtaglomerular cell tumor (JCT) was successfully treated with the calcium channel blocker nifedipine until surgical removal effected a permanent cure. This case was incorporated into a review of the 37 cases previously published. Comparison of the children and adolescents with the adult population showed that the features of JCT were similar in the two groups except for the average duration of symptoms prior to diagnosis (pediatric group 2.6 years vs. 6.0 years for the adult group). Analysis of all 38 cases demonstrated the following: 1. Teenagers constituted the largest single population with JCT (39%) and approximately two-thirds of the entire population were female. 2. Many patients failed to show persistent hypokalemia despite high plasma renin activity and secondary hyperaldosteronism. 3. Renal angiography was initially negative in more than half the cases. 4. Renal vein renin failed to show lateralization to the affected kidney in 52% of the cases. 5. Computerized tomography demonstrated a renal mass in all of the cases in which it was performed, even when other imaging studies were negative. 6. Calcium channel blockers may evolve as the preferred treatment for the high renin hypertension of JCT.

We describe a rare case of renal hypertension in a 15-year-old caused by juxtaglomerular cell tumor and compare our findings with those of 20 children reported in the literature. These tumors are usually encapsulated and composed microscopically of polyhedral cells with bland nuclei separated by fibrovascular septa. Characteristic renin granules can be demonstrated by Bowie\'s stain or electron microscopy. These tumors are benign. Pathologists should recognize the morphologic characteristics of these tumors when dealing with renin-producing neoplasia.