Juxtaglomerular Tumor Research Articles

Immunohistochemical expression of renin and 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. Although 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 years), 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.

Glomus Tumor of the Kidney: Case report

Abstract Introduction: Glomus tumors are rare benign mesenchymal neoplasms accounting for only 2% of all types of soft tissue tumors. Commonly located in the peripheral soft tissues, they are most frequently encountered in the subungual areas of fingers and toes, and very rarely in visceral organs due to the absence of glomus bodies. To date, 22 cases of primary renal glomus tumors have been described in the literature, of which 17 benign, with no evidence of recurrence or metastasis, three cases of malignant glomus tumor, and two cases with uncertain malignant potential. Case report: We report the 18th case of a benign glomus tumor of the kidney in a 49-year-old female patient, presenting the microscopic appearance (round, uniform cells with indistinct borders, scant finely granular eosinophilic cytoplasm, round nuclei lacking prominent nucleoli, arranged in solid sheets, accompanied by slit-like vascular spaces), the immunohistochemical profile (tumor cells showed immunoreactivity for smooth muscle actin, vimentin, as well as for CD34; they were negative for AE1/AE3, desmin, HMB-45, S-100 protein, renin, and chromogranin), and the differential diagnosis of this rare entity (juxtaglomerular tumor, angiomyolipoma, hemangioma, epithelioid leyomioma, solitary fibrous tumor, carcinoid tumor, and paraganglioma). Conclusion: Primary renal glomus tumors are rare tumors that radiologically can mimic other mesenchymal renal neoplasm. Accurate diagnosis is based on the microscopic appearance and especially the characteristic immunophenotype.

Treatment of a Juxtaglomerular Tumour with Radiofrequency Ablation

Juxtaglomerular tumors, or reninomas, are a rare cause of hypertension, almost always benign and accurately localized by a combination of biochemical tests and imaging. Because the tumors are usually small at presentation, and there are good markers for recurrence, we consider treatment by radiofrequency ablation a useful alternative to nephron-sparing surgery and describe its use in one patient.

A Case of Renin-producing Juxtaglomerular Tumor: Effect of ACE Inhibitor or Angiotensin II Receptor Antagonist

Kashiwabara H, Inaba M, Itabashi A, Ishii J, Katayama S. A case of renin-producing juxtuglomerular tumor: effect of ACE inhibitor or angiotensin II receptor antagonist.We report a case of a renin-producing juxtaglomerular cell tumor and the effects of angiotensin-converting enzyme (ACE) inhibitor captopril or angiotensin II receptor antagonist TCV-116. xsA 19-year-old female visited our clinic because of hypertension (162/122 mmHg). Plasma renin activity (PRA) was 25 ng/ml/h and plasma aldosterone concentration (PAC) was 880 pg/ml. Abdominal sonography revealed a low echoic tumor in the center of the right kidney. The mass was shown to have isodensity on a computed tomography scan, iso- or slightly lower intensity on T1–weighted magnetic resonance imaging (MRI), and low intensity on T2-weighted MRI. Renal angiography disclosed a hypovascular tumor. Plasma renin activity was not decreased in response to oral administration of captopril (50 mg) or TCV-116 (4 mg), which is associated with a marked decrease in PAC and blood pressure. The average of the mean blood pressure determined by an ambulatory monitoring system every hour for 24 h was lowered from 118–t 10.6 (SD) to 85 t 11.4 mmHg by TCV-116. Plasma renin activity did not show any difference between the right and left renal vein. Removal of the tumor successfully decreased PRA to 0.3 ng/ml/h and PAC to 33 pg/ml, resulting in a decrease in 24–h average of the mean blood pressure to 78 ± 16.9 mmHg. The tumor was well capsulated and stained with an antibody against mouse renin. In the tumor, but not normal tissues, renin mRNA was detected at 1.6 kb using rat renin cDNA. The content of active renin in the tumor amounted to 182pg/g tissue, which is 109 times higher than that in normal tissue. The plasma- or tumor-inactive renjn concentration was 3.6- or 1.8-fold the active renin concentration, respectively. These results suggest that the juxtaglomerular tumor had an MRI image of iso- to low intensity on TI and low intensity on T2, and that renin secretion from the tumor may be due mainly to the constitutive pathway and angiotensin II receptor antagonist, as well as to ACE inhibitors, and may be very effective for lowering the blood pressure.

Long-term preservation of renin-secreting ability by human adult juxtaglomerular tumor cells in explant culture.

Studies on cultured human renin(R)‐producing tumors cells are few. In this work the R secretion by a human Juxtaglomerular tumor (JGT) in various tissue culture models was evaluated by a new immunoradiometric assay. Freshly isolated JGT cells actively secreted total R (tR; about 70% of which is proR) into the perfusion media of very short‐term cultures (tR concentration, 100–400 ng/ml/106 cells), independently of factors stimulating or inhibiting R output by normal JG cells. Primary monolayer cultures of the same JGT rapidly lost their tR‐secreting capability and died by apoptosis within two months. Conversely, a JGT explant survived for up to 22 months in vitro. During the first year of culture, this explant increased in volume and generated, at 3‐ to 4‐monthly intervals, several self‐limited cellular outgrowths, from which it became detached. Meanwhile, tR secretion by the explant decreased very slowly, though its decline was transiently and partly reversed by various combinations of growth factors, hormones, a prostaglandin, and selenous acid added to either a serum‐enriched or a synthetic medium. By the 12th month in vitro, tR secretion had faded away. Like the primary monolayers, the various explant outgrowths, once detached, stopped secreting tR and died in a few weeks. Hence, the preservation of a histiotypic relationship and the actions of several mitogenic and/or differentiating agents are essential for the long‐term survival and the continuance of R secretion by human JGT cells in vitro.

Response of plasma prorenin and active renin to chronic and acute alterations of renin secretion in normal humans. Studies using a direct immunoradiometric assay.

We employed a novel immunoradiometric assay to measure plasma levels of active renin and prorenin in physiologic and pharmacologic studies designed to characterize renin biosynthesis and processing in response to both chronic and acute stimuli of renin secretion in normal human subjects. Stimulation of renin secretion with prolonged dietary sodium restriction or amiloride resulted in marked increases in the plasma levels of prorenin, active renin, and plasma renin activity (PRA); suppression of renin secretion with indomethacin resulted in parallel decreases in prorenin, active renin, and PRA. In contrast, acute stimulation with upright activity or administration of an angiotensin-converting enzyme inhibitor, which increased active renin and PRA from 2- to 15-fold, had no effect on prorenin levels. Based on studies in cultured human juxtaglomerular tumor cells, it has been proposed that prorenin is secreted constitutively whereas active renin is stored in and released from secretory granules through a regulated pathway. Our studies are consistent with such a model: the parallel changes in active renin and prorenin with experimental maneuvers of long duration suggest that both the constitutive and regulated pathways are altered under these conditions. The increase in active renin levels in the absence of a change in prorenin that occurs in response to acute stimuli presumably represents the release of preformed active enzyme that is stored in secretory granules.

Immunoreactive prorenin and its profragment peptide are present in human juxtaglomerular cells.

Although prorenin appears to be activated through the cleavage of its prosegment in the juxtaglomerular cells, the presence of prosegment peptide has never been demonstrated. We therefore studied prorenin in juxtaglomerular tumour cells, both by immunohistochemistry and by radio-immunoassay. Synthetic peptide covering the 14-carboxyterminal sequence of human renin prosegment was used to prepare both antibody and radiolabelled tracer. Intense immunostaining of prorenin was demonstrated in the tumour cells. By gel filtration, however, immunoreactive prorenin was shown to consist of two major components. The first peak, located at the elution position of activatable inactive renin, was regarded as prorenin. The other peak was located at an elution position with a smaller molecular weight, which was assumed to represent the profragment. These results suggest that both prosegment peptide and prorenin are present in the juxtaglomerular cells.

The radiology of juxtaglomerular tumors.

Nine cases of proven juxtaglomerular tumor of the kidney are reviewed. Each patient presented with hypertension; elevated peripheral renin levels were found in four patients. As in past studies, this tumor occurred more frequently in women (7/9 cases). Although the patients tended to be younger (mean age, 31 years) than those with essential hypertension, all but two patients were more than 20 years of age. In all cases, the tumor was solitary, well-defined, and curable by surgery. The tumor was identified by excretory urography in 5/8 patients who underwent this procedure. A solid renal mass was detected in each of the seven patients examined by ultrasound. Since the tumor tends to be isodense with normal renal parenchyma, it is sometimes not seen on computed tomography without intravenous contrast material. Arteriography revealed a hypovascular mass in each of the nine patients. The combination of a hypovascular solid renal mass in a patient with elevated renin but no renal artery lesions should suggest the diagnosis of a juxtaglomerular cell tumor.

Immunohistochemistry of renin in human diseased kidney.

The distribution of renin in human kidney was investigated by immunofluorescence and the peroxidase-antiperoxidase (PAP) procedure at the light and ultrastructural level. In three cases of juxtaglomerular renin-secreting tumors, renin was localized within the cytoplasm of tumor cells. In kidney biopsies, a semi-quantitative assessment was carried out, taking into account the size and the number of immunostained juxtaglomerular apparatuses. In 12 cases of ischemic kidneys and 8 cases of segmental renal hypoplasia, the increase in immunostaining for renin was striking in altered areas, while spared areas remained negative. In 2 cases of Bartter's syndrome, the pattern was similar to that found in ischemic kidneys. The study was extended to a series of 133 needle kidney biopsies from patients with various glomerular and vascular diseases; the immunomorphological parameters were correlated with serum creatinine levels but not with blood pressure values. Post-embedding immunoelectronmicroscopy using the PAP procedure performed on two of the cases of renin-secreting tumors, showed renin in all types of secretory granules.