Review of juxtaglomerular cell tumor with focus on pathobiological aspect.

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.

Juxtaglomerular cell tumor of the kidney: case report and differential diagnosis with emphasis on pathologic and cytopathologic features.

This study presents a case of juxtaglomerular cell tumor (JCT) in a 12-year-old girl with hypertension. Fine needle aspirate (FNA) cytology demonstrated a neoplasm with features of a papillary carcinoma, prompting a right radical nephrectomy. Histological examination revealed solid sheets of round epithelioid cells with eosinophilic granular cytoplasm, and distinct cell borders in a background of widespread hemorrhage. Electron microscopy revealed cytoplasmic renin granules. The differential diagnosis of a renal mass in a young patient with hypertension includes JCT, Wilm's tumor, and renal cell carcinoma, which may produce renin. The renin granules detected by electron microscopy are characteristic of JCT, and the diagnosis is confirmed by ultrastructural study. FNA cytology is not sensitive enough for the diagnosis of JCT and its results must be carefully interpreted.

A kidney tumor in an adolescent with severe hypertension and hypokalemia: an uncommon case--case report and review of the literature on reninoma.

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.

[Juxtaglomerular cell tumors: report of two cases with genomic analysis]. / Tumeur à rénine du rein : à propos de deux cas, avec analyse génomique.

Juxtaglomerular-cell tumor (JGCT), first described in 1967, is a rare tumor of the kidney that derives from specialized smooth-muscle cells of the wall of the glomerular afferent arteriole. Less than 100 cases have been published, mainly as single-case reports or small series. JGCTs are considered benign, but the clinical follow-up has been short in most reported cases. Only one metastatic case has been reported to date, raising the question of tumors of uncertain malignant potential rather than clearly benign neoplasms. Genomic features have been studied in only two cases that showed gains on chromosome 10 as well as deletions on chromosomes 9, 11q and X. The present work studied the genomic characteristics of two additional cases of JGCT by CGH. Similarly to the two previously reported cases, these two tumors showed losses on chromosomes 9 and 11, suggesting recurrent chromosomal imbalances. In addition, one case showed gains and losses of entire chromosomes similar to a previous case studied by karyotyping. Such an aneuploid karyotype may reflect a potential for malignancy as previously reported. Thus, JGCT might be better considered as a tumor of uncertain malignant potential consequently requiring a prolonged follow-up. Future clinicopathologic and genomic studies of large retrospective and prospective series may help to better understand the biology of this fascinating entity.

Myocardial infarction in a young female with reninoma induced hypertension and myocardial bridging.

We present a case of myocardial infarction in a young female with reninoma induced hypertension and myocardial bridging. Reninoma is a rare and curable cause of secondary hypertension. Currently developed multi-detector computed tomography (MDCT) has permitted better evaluation of myocardial infarction and myocardial bridging. Myocardial infarction associated with reninoma and myocardial bridging has not been reported, and we report this interesting case.

Juxtaglomerular apparatus tumor: a rare but curable cause of secondary hypertension.

We have reported our experience at Duke University Medical Center with juxtaglomerular apparatus tumor, a rare but remediable cause of significant hypertension. Our three cases illustrate markedly different clinical courses and diagnostic difficulties. Results of the usual diagnostic studies, including intravenous pyelogram and renal angiogram with selective renal vein renin assessment, may be normal, but abdominal CT with contrast can show even small lesions. Thus we propose the addition of CT in evaluating all cases of high-renin hypertension when renal artery stenosis has been excluded. Periodic reevaluation of these patients is mandatory to increase diagnostic accuracy and avoid unnecessary morbidity and mortality. Local resection, rather than total nephrectomy, should be considered because the tumors have low invasive potential.

Superficial and deep juxtaglomerular apparatus renin activity of the rat kidney. Effect of surgical preparation and NaCl intake.

The intrarenal gradient of renin activity was determined in rats by using superficial (S) and deep (D) cortical juxtaglomerular apparatuses (JGA's), identified and microdissected after silicone-rubber compound injection. Angiotensin generated from single JGA's using partially purified sheep renin substrate was quantified by rat bioassay. When, in rats on a normal NaCl diet, silicone-rubber was injected into a carotid artery, alone or with abdominal aorta catheterization, S:D renin activity ratios were 1.18+/-0.08 (SEM) and 1.21+/-0.12, respectively. The S:D renin activity ratios obtained when silicone-rubber was injected into the abdominal aorta (2.52+/-0.09) or a chronic carotid artery catheter (3.44+/-0.40) were significantly higher (P < 0.001). The lower S:D renin activity ratios after carotid artery manipulation were due to significantly higher D-JGA renin activities. This increased D-JGA renin activity and the lack of a renin gradient appear to be related to acute carotid artery manipulation. Alterations in JGA renin activity were examined relative to NaCl intake. 2 wk after high-NaCl diet the absolute net renin activity decreased (P < 0.001) more in S (5.84+/-0.11 ng AI.JGA(-1).h(-1)) than D (1.73+/-0.06 ng AI.JGA(-1).h(-1)) JGA's, and the intrarenal renin gradient was lost (S:D-JGA renin activity, 1.00+/-0.07), as compared to the regular NaCl diet. 2 wk of a low-NaCl diet resulted in a greater (P < 0.01) increase in S (14.28+/-1.47 ng AI.JGA(-1).h(-1)) than D (9.62+/-1.19 ng AI.JGA(-1).h(-1)) JGA renin activity and a renin gradient (S:D-JGA renin activity) of 1.75+/-0.12. These results demonstrate that NaCl intake clearly influences total JGA renin content and may also affect the relative intrarenal distribution of renin activity.