Juxtaglomerular cell tumor: a morphological, immunohistochemical and genetic study of six cases

Renal Juxtaglomerular Cell Tumors Exhibit Distinct Genomic and Epigenomic Features and Lack Recurrent Gene Fusions: Comprehensive Molecular Analysis of a Multi-institutional Series

Juxtaglomerular cell tumor (JxGCT) is a rare type of renal neoplasm demonstrating morphologic overlap with some mesenchymal tumors such as glomus tumor (GT) and solitary fibrous tumor (SFT). Its oncogenic drivers remain elusive, and only a few cases have been analyzed with modern molecular techniques. In prior studies, loss of chromosomes 9 and 11 appeared to be recurrent. Recently, whole-genome analysis identified alterations involving genes of MAPK-RAS pathway in a subset, but no major pathogenic alterations have been discovered in prior whole transcriptome analyses. Considering the limited understanding of the molecular features of JxGCTs, we sought to assess a collaborative series with a multiomic approach to further define the molecular characteristics of this entity. Fifteen tumors morphologically compatible with JxGCTs were evaluated using immunohistochemistry for renin, single-nucleotide polymorphism array (SNP), low-pass whole-genome sequencing, and RNA sequencing (fusion assay). In addition, methylation analysis comparing JxGCT, GT, and SFT was performed. All cases tested with renin (n=11) showed positive staining. Multiple chromosomal abnormalities were identified in all cases analyzed (n=8), with gains of chromosomes 1p, 10, 17, and 19 and losses of chromosomes 9, 11, and 21 being recurrent. A pathogenic HRAS mutation was identified in one case as part of the SNP array analysis. Thirteen tumors were analyzed by RNA sequencing, with 2 revealing in-frame gene fusions: TFG::GPR128 (interpreted as stochastic) and NAB2::STAT6 . The latter, originally diagnosed as JxGCT, was reclassified as SFT and excluded from the series. No fusions were detected in the remaining 11 cases; of note, no case harbored NOTCH fusions previously described in GT. Genomic methylation analysis showed that JxGCT, GT, and SFT form separate clusters, confirming that JxGCT represents a distinct entity (ie, different from GT). The results of our study show that JxGCTs are a distinct tumor type with a recurrent pattern of chromosomal imbalances that may play a role in oncogenesis, with MAPK-RAS pathway activation being likely a driver in a relatively small subset.

Renal Neoplasia: Rare Subtypes and Uncommon Clinical Presentations

Herein, the authors have discussed a series of uncommon familial kidney cancer syndromes (including hyperparathyroidism-jaw tumor syndrome and PTEN hamartoma tumor syndrome), sporadically occurring tumors (BRAF and MTOR pathway-mutated tumors, and juxtaglomerular cell tumors), and uncommon patterns of well-established subtypes of kidney cancer (mucinous tubular spindle cell carcinoma, fumarate hydratase-deficient, and TFE3-rearranged renal cell carcinoma). The rarity of these tumors often leads to diagnostic odysseys for pathologists and patients. Appropriate classification of these rare tumors has implications for screening at-risk family members in the case of hereditary tumor predisposition syndromes, accurate prognostication, and appropriate patient selection for clinical trials.

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.

Hallmark discoveries in the biology of non-Wilms tumour childhood kidney cancers

Approximately 20% of paediatric and adolescent/young adult patients with renal tumours are diagnosed with non-Wilms tumour, a broad heterogeneous group of tumours that includes clear-cell sarcoma of the kidney, congenital mesoblastic nephroma, malignant rhabdoid tumour of the kidney, renal-cell carcinoma, renal medullary carcinoma and other rare histologies. The differential diagnosis of these tumours dates back many decades, when these pathologies were identified initially through clinicopathological observation of entities with outcomes that diverged from Wilms tumour, corroborated with immunohistochemistry and molecular cytogenetics and, subsequently, through next-generation sequencing. These advances enabled near-definitive recognition of different tumours and risk stratification of patients. In parallel, the generation of new renal-tumour models of some of these pathologies including cell lines, organoids, xenografts and genetically engineered mouse models improved our understanding of the development of these tumours and have facilitated the identification of new therapeutic targets. Despite these many achievements, paediatric and adolescent/young adult patients continue to die from such rare cancers at higher rates than patients with Wilms tumour. Thus, international coordinated efforts are needed to answer unresolved questions and improve outcomes.

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.

Targetable NOTCH1 rearrangements in reninoma

Reninomas are exceedingly rare renin-secreting kidney tumours that derive from juxtaglomerular cells, specialised smooth muscle cells that reside at the vascular inlet of glomeruli. They are the central component of the juxtaglomerular apparatus which controls systemic blood pressure through the secretion of renin. We assess somatic changes in reninoma and find structural variants that generate canonical activating rearrangements of, NOTCH1 whilst removing its negative regulator, NRARP. Accordingly, in single reninoma nuclei we observe excessive renin and NOTCH1 signalling mRNAs, with a concomitant non-excess of NRARP expression. Re-analysis of previously published reninoma bulk transcriptomes further corroborates our observation of dysregulated Notch pathway signalling in reninoma. Our findings reveal NOTCH1 rearrangements in reninoma, therapeutically targetable through existing NOTCH1 inhibitors, and indicate that unscheduled Notch signalling may be a disease-defining feature of reninoma.

Malignant juxtaglomerular cell tumor

Juxtaglomerular cell tumors (JGCTs) are rare, typically benign neoplasms; only rare cases are clinically or histologically malignant. We herein report the histologic, immunophenotypic, and molecular features of a clinically unsuspected, diagnostically challenging case of malignant JGCT in a 23-year-old man. The diagnosis is confirmed with electron microscopy. The case is notable for its marked mitotic activity, which has not been previously reported in JGCTs, and novel finding of GATA3 immunohistochemical positivity.

Juxtaglomerular cell tumor: report of a case with unusual presentation

Juxtaglomerular cell tumor is a benign, renin-secreting neoplasm. The tumor arises from the juxtaglomerular apparatus cells of the kidney. Because the tumor is hormonally active, patients usually suffer from hypokalemia, hyperaldosteronism, and hypertension. Herein, we describe a case of a 19-year-old Asian female with a somewhat unusual presentation.

A 19-year-old Asian female presented with upper extremity weakness, numbness, and tingling. On physical examination, the only notable finding was hypertension. Extensive workup revealed elevated aldosterone level and plasma renin activity. CT scan of the abdomen revealed a 2.2 cm mass in the lower pole of the left kidney. The mass was resected by partial nephrectomy. On microscopic evaluation, the tumor had glomoid appearance with sheets of uniform, round to polygonal cells with clear to eosinophilic cytoplasm. Immunohistochemical stains showed the tumor cells to be positive for CD117, CD34 and CD10 and negative for ER, PR, CK7, PAX-8, pan-cytokeratin, EMA, S100, Melan-A, HMB45, SMA and CAIX. Diagnosis of Juxtaglomerular cell tumor was rendered. This case highlights the importance of a regular physical exam and a high index of suspicion in patients presenting with unusual complaints.

Immunohistochemical Expression of Renin & GATA3 Help Distinguish Juxtaglomerular Cell Tumors from Renal Glomus Tumors

Juxtaglomerular cell tumors and glomus tumors both arise from perivascular mesenchymal cells. Juxtaglomerular cells are specialized renin-secreting myoendocrine cells in the afferent arterioles adjacent to glomeruli, and juxtaglomerular tumors derived from these cells are therefore unique to the kidney. In contrast, glomus tumors have been described at numerous anatomic sites and may show significant morphologic and immunophenotypic overlap with juxtaglomerular tumors when occurring in the kidney. While ultrastructural studies and immunohistochemistry for renin may distinguish these entities, these diagnostic modalities are often unavailable in routine clinical practice. Herein, we studied the clinicopathologic features of a large series of juxtaglomerular tumors (n=15) and glomus tumors of the kidney (n=9) to identify features helpful in their separation, including immunohistochemistry for smooth muscle actin (SMA), CD34, collagen IV, CD117, GATA3, synaptophysin, and renin. Markers such as SMA (juxtaglomerular tumors: 12/13, 92%; glomus tumors: 9/9, 100%), CD34 (juxtaglomerular tumors: 14/14, 100%; glomus tumors: 7/9, 78%), and collagen IV (juxtaglomerular tumors: 5/6, 83%; glomus tumors: 3/3, 100%) were not helpful in separating these entities. In contrast to prior reports, all juxtaglomerular tumors were CD117 negative (0/12, 0%), as were glomus tumors (0/5, 0%). Our results show that juxtaglomerular tumors have a younger age at presentation (median age: 27), female predilection, and frequently exhibit diffuse positivity for renin (10/10, 100%) and GATA3 (7/9, 78%), in contrast to glomus tumors (median age: 51 years; renin: 0/6, 0%; GATA3: 0/6, 0%). These findings may be helpful in distinguishing these tumors when they exhibit significant morphologic overlap.

Key Renal Neoplasms With a Female Predominance

Renal neoplasms largely favor male patients; however, there is a growing list of tumors that are more frequently diagnosed in females. These tumors include metanephric adenoma, mixed epithelial and stromal tumor, juxtaglomerular cell tumor, mucinous tubular and spindle cell carcinoma, Xp11.2 (TFE3) translocation-associated renal cell carcinoma, and tuberous sclerosis complex (somatic or germline) associated renal neoplasms. The latter category is a heterogenous group with entities still being delineated. Eosinophilic solid and cystic renal cell carcinoma is the best-described entity, whereas, eosinophilic vacuolated tumor is a proposed entity, and the remaining tumors are currently grouped together under the umbrella of tuberous sclerosis complex/mammalian target of rapamycin-related renal neoplasms. The entities described in this review are often diagnostic considerations when evaluating renal mass tissue on biopsy or resection. For example, Xp11.2 translocation renal cell carcinoma is in the differential when a tumor has clear cell cytology and papillary architecture and occurs in a young or middle-aged patient. In contrast, tuberous sclerosis complex-related neoplasms often enter the differential for tumors with eosinophilic cytology. This review provides an overview of the clinical, gross, microscopic, immunohistochemical, genetic, and molecular alterations in key renal neoplasms occurring more commonly in females; differential diagnoses are also discussed regardless of sex predilection.

Spindle Cell Hemangioma and Atypically Localized Juxtaglomerular Cell Tumor in a Patient with Hereditary BRIP1 Mutation: A Case Report

Spindle cell hemangioma is a benign vascular tumor typically occurring in the dermis or subcutis of distal extremities as red-brown lesions that can grow in both size and number over time. They can be very painful and potentially disabling. A family history of cancer or previous history may be relevant and must be taken into consideration. Juxtaglomerular cell tumor (reninoma) is an extremely rare cause of secondary hypertension diagnosed mostly among adolescents and young adults. Excessive renin secretion results in secondary hyperaldosteronism. Subsequent hypokalemia and metabolic alkalosis, together with high blood pressure, are clues for clinical diagnosis. Histological examination of the excised tumor leads to a definitive diagnosis. Reninoma is found in subcapsular localization, in most cases as a solitary mass, in imaging studies of kidneys. Exceptionally, it can be located in another part of a kidney. Both spindle cell hemangioma and reninoma are extremely rare tumors in children and adolescents. Herein, the authors present a case report of a patient with hereditary BRCA1 interacting protein C-terminal helicase 1 (BRIP1) mutation, spindle cell hemangioma, and secondary hypertension caused by atypically localized reninoma.

The Small Size and Superficial Location Suggest That Laparoscopic Partial Nephrectomy Is the First Choice for the Treatment of Juxtaglomerular Cell Tumors

BACKGROUND

Juxtaglomerular cell tumor (JGCT) is a very rare disease, and surgical resection is the only possible way to cure this tumor. Open nephrectomy and partial nephrectomy have been reported to manage JGCTs with excellent results in the previous reviews. Laparoscopic surgery has been popularized in recent years, while critical issues associated with laparoscopic surgical management have been seldom reported. We summarized the JGCTs in our center to discover the optimal surgical management and its anatomic foundation.

METHODS

In this retrospective study, we enrolled a total of 14 JGCT patients. All patients received surgeries and were followed up for up to 11 years. We mainly summarized the size and location of tumors, imaging features, and surgical strategies. A descriptive statistical analysis was performed.

RESULTS

The JGCTs in this study had a median size of 1.35 cm and all located superficially, mainly in the cortical or subcortical area of the kidney. All 14 patients had hypertension, ten had hypokalemia, and seven had elevated plasma renin activity. Pathologically, JGCT cells were polygonal or spindle shape, with positive CD34 and vimentin immunostaining. All patients received partial nephrectomy; nine were laparoscopic, and five were open. Laparoscopic partial nephrectomy (LPN) was performed in seven out of eight patients over the last nine years. Postoperative blood pressure, serum potassium, and plasma renin activity were normal in all patients. No recurrence occurred within a median follow-up of 60 months.

CONCLUSION

The small size and superficial location are the characteristic anatomic features of JGCT; they suggest that LPN is the preferred surgical strategy. Laparoscopic ultrasound is helpful for the intraoperative detection of small JGCTs. Longer follow-up is required to examine the biological behavior of JGCTs and the effect of LPN.

JUXTAGLOMERULAR CELL CAUSE OF SECONDARY HYPERTENSION IN AN ADOLESCENT

Reninoma (juxtaglomerular cell tumor) is a rare cause of renin-mediated hypertension. We reported a 18 year old woman with history of hypertension for 3 years. Laboratory findings showed severe hypokalemia and markedly increased levels of renin and aldosterone. Kidney ultrasonography, abdominal computed tomography and magnetic resonance imaging revealed a small mass in the middle region of the right kidney. The patient underwent nephron-sparing surgery; immunohistochemical results demonstrated typical features of reninoma. Postoperatively, blood pressure and potassium levels were normal at 1 month follow-up.

Juxtaglomerular Cell Tumor With Atypical Pathological Features: Report of a Case and Review of Literature

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.

Minimally Invasive Surgery-Based Multidisciplinary Clinical Management of Reninoma: A Single-Center Study

Background

This article presents our experience in managing a rare kidney tumor – reninoma – by analyzing a relatively large series of cases from a single center.

Material/Methods

Nine cases of reninoma were reviewed. Clinical manifestations, imaging examinations, laboratory examinations, perioperative data, and pathological findings were summarized. A 58.8-month follow-up was performed to evaluate patient survival and recrudescence.

Results

The main clinical manifestations were hypertension, hypokalemia, headache, dizziness, nausea, vomiting, palpation, and sweating. Three patients had hypertensive end-organ damage, including brain hemorrhage, gestation termination, and grade III ocular fundus changes. All patients underwent retroperitoneal laparoscopic partial nephrectomy successfully. The mean warm ischemic time was 23.4 min. The median operation time was 95.1 min, with a median estimated blood loss of 60 ml. The median hospital stay was 6 days. No serious intraoperative or postoperative complications occurred. The histology and electron microscopy findings confirmed the diagnosis of reninoma in all cases. After 58.8 months of follow-up, symptoms involving hypertension were relieved in all patients, and no tumor recurrence or metastasis was detected.

Conclusions

Reninoma may have severe consequences despite being a benign tumor. Retroperitoneal laparoscopic partial nephrectomy is a feasible and effective method for the surgical removal of reninoma. Multidisciplinary cooperation plays an important role in improving the diagnosis and enabling the early surgical treatment of reninoma. Especially in cases of reninoma with moderate and high RENAL scores, an accurate diagnosis of reninoma based on multidisciplinary cooperation facilitates the selection of less invasive surgical approaches.

Mesenchymal Neoplasms of the Genitourinary System: A Selected Review with Recent Advances in Clinical, Diagnostic, and Molecular Findings

Mesenchymal neoplasms of the genitourinary (GU) tract often pose considerable diagnostic challenges due to their wide morphologic spectrum, relative rarity, and unexpected incidence at GU sites. Soft tissue tumors arise throughout the GU tract, whether from adventitia surrounding or connective tissues within the kidneys, urinary bladder, and male and female genital organs. This selected article focuses on a subset of these lesions, ranging from benign to malignant and encompassing a range of patterns of mesenchymal differentiation, where recent scholarship has lent greater insight into their clinical, molecular, or diagnostic features.

Case Report of Atypical Juxtaglomerular Cell Tumor

Juxtaglomerular cell tumor (JGCT) is a rare renal tumor, producing renin and behaving almost in a benign fashion. So far, only three cases have been reported as malignant. We report a rare case with atypical JGCT. A 74-year-old male was referred to our hospital due to hypertension, proteinuria, and hematuria. Abdominal CT revealed a mass measured in 9.7×7.0 cm in the lower portion of the right kidney. Right kidney was removed laparoscopically. Grossly, white to tan tumor with massive hemorrhage and necrosis occupied the lower portion of the right kidney. Microscopically, tumor grew in a solid fashion. Tumor cells were polygonal to ovoid cells with round nuclei and clear to eosinophilic cytoplasm. Mitosis was found in 5 per 10 HPF. Immunohistochemically, tumor cells were stained by vimentin and CD34. Some tumor cells were also positive for renin. Electron micrograph showed near rhomboid crystalline structure in the tumor cells. Because of massive necrosis and mitotic figures, diagnosis of atypical (potentially malignant) JGCT was rendered. Gene mutations for IDH1, PIK3CA, K-ras, N-ras, Braf, and EGFR were not found by MBP-QP system.

Juxtaglomerular cell tumor: Clinical and immunohistochemical features

Juxtaglomerular cell tumor (JGCT) is a rare tumor, with approximately 100 cases reported in the literature. The authors respectively studied the clinical data of 11 patients diagnosed with JGCT in Peking Union Medical College Hospital from 2004 to 2014, and investigated the immunohistochemical profiles in 10 tumors. Nine of the 11 patients were diagnosed before the age of 40 years. Hypertension was present in all patients, while hypokalemia occurred in seven of 11 patients. Computed tomography detected JGCTs with a sensitivity of 100%. Immunoreactivities for CD34 and vascular endothelial growth factor were observed in most tumor specimens, suggesting that JGCTs express a variety of vessel-related immunohistochemical markers, although JGCTs are considered a tumor without abundant blood supply. Nuclear accumulation of cyclin D1 was common in JGCTs. Results from immunohistochemistry were negative for BRAF, HER2, and TFE3, suggesting that BRAF, HER2, and TFE3 genes might not play a part in tumorigenesis in JGCTs.

Magnetic Resonance Imaging Features of a Juxtaglomerular Cell Tumor

OBJECTIVE

To retrospectively determine whether magnetic resonance imaging (MRI) findings can help differentiate a juxtaglomerular cell tumor (JCT) from clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

Eight patients with JCTs and 24 patients with pathologically proven ccRCC were included for image analysis. All patients underwent unenhanced MRI and dynamic contrast-enhanced MRI. Fat-suppressed T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), in- and opposed-phase imaging, and fat-suppressed preliver acquisitions with volume acceleration sequences were performed before enhancement. After the administration of contrast, dynamic imaging was performed in the corticomedullary, nephrographic, and excretory phases. Student's t-test, t'-test, Chi-square test, and nonparametric Kruskal-Wallis H-test were used to determine the significance of the difference between the two groups. The sensitivity and specificity of the MRI findings were calculated.

RESULTS

In patients with a JCT, a cystic part of the lesion of <10%, isointensity or mild hyperintensity on T2WI, heterogeneous hyperintensity on DWI, less signal drop (<10%) in in- and opposed-phase imaging, and a degree of enhancement <200% in the corticomedullary phase showed statistically significant differences compared with those of ccRCC (P < 0.05). After combining a lower apparent diffusion coefficient (ADC) value (heterogeneous hyperintensity) on DWI and a degree of enhancement <200% in the corticomedullary phase using a parallel test, the sensitivity and specificity were 90.9% and 91.7%, respectively.

CONCLUSIONS

Isointensity or mild hyperintensity on T2WI, a lower ADC value (heterogeneous hyperintensity) on DWI, and a degree of enhancement <200% in the corticomedullary phase are the major MRI findings for JCTs, combined with relative clinical manifestations and excluding other renal masses. A main solid tumor, less signal drop (<10%) in in- and opposed-phase imaging, and a less-washout pattern of <10% in the delayed phase are secondary MRI findings for JCTs.

Juxtaglomerular cell tumor: A case report

The current study reports the case of a 29-year-old female with a long-standing history of hypertension and headaches who presented to the Outpatient Clinic of The Central Hospital of Lishui (Lishui, Zhejiang, China). Abdominal ultrasound and contrast-enhanced computed tomography were performed, which showed a left renal neoplasm, prompting a diagnosis of renal angiomyolipoma or renal cell carcinoma. After a laparoscopic partial nephrectomy was performed, a number of different diagnoses were suggested by several pathologists from eight hospitals. Considering the patient's gender, age, medical history, histopathological features and immunohistochemistry, a final diagnosis of a juxtaglomerular cell tumor (JGCT) was established. The present study therefore indicates that the possibility of a JGCT should be considered when young adults present with renal parenchymatous tumors and high blood pressure. In addition, pathologists must take clinical information into account to form a precise diagnosis.

Adult Pleomorphic Juxtaglomerular Cell Tumor

A 40-year-old male with chronic hypertension since his teens presented to the emergency department following a motor vehicle collision. Computed tomography scan demonstrated an incidental 1.8-cm renal mass. Partial nephrectomy revealed a vascular tumor with predominantly monomorphic epithelioid cells arranged in sheets and trabeculae with foci of nuclear pleomorphism. Tumor cells were positive for vimentin, CD34, and c-KIT. Juxtaglomerular cell tumor is a rare, benign neoplasm typically found in young adults. Pleomorphism is uncommon and, in combination with older age at diagnosis, can lead to an inaccurate malignant diagnosis. Immunohistochemistry and clinical history helps in correctly diagnosing this benign entity.

Reninoma: an uncommon cause of Renin-mediated hypertension

Reninoma (juxtaglomerular cell tumor) is a rare cause of renin-mediated hypertension. Reninomas are usually diagnosed in adolescents and young adults with occasional reports in younger children. Patients typically present with a long history of headaches leading to a diagnosis of severe hypertension that responds well to antihypertensive treatment targeting the renin-angiotensin-aldosterone system. The clue to clinical diagnosis is the presence of hypokalemia and metabolic alkalosis on the first blood sample drawn before any treatment is instituted. Elevated blood levels of renin and aldosterone confirm the clinical suspicion of renin-mediated hypertension. Diagnostic imaging is employed to identify the source of excessive renin production. While renal ultrasound can miss reninoma, contrast CT or magnetic resonance imaging of the kidneys are diagnostic modalities of choice leading to the correct diagnosis. Renal vein renin sampling with lateralization might help to identify the site of excessive renin production. Nephron-sparing surgery is curative with maintenance of normal blood pressure after discontinuation of antihypertensive medications in the majority of patients. In this paper, we present the case of reninoma in an adolescent girl emphasizing clinical presentation, diagnostic evaluation, and medical and surgical treatment of this rare tumor. We also discuss important points in the management of children presenting with renin-mediated hypertension.

[Treatment by radiofrequency ablation for a renin-secreting juxtaglomerular tumour: a case report]

Juxtaglomerular cell tumors are rare and benign tumors, occurring in young patients. The standard treatment is partial nephrectomy. We report the case of a young 22-year-old patient with a renin-secreting tumor diagnosed during an exploration of severe hypertension associated with hypokalemia that we treated by radiofrequency ablation.