Juxtaglomerular cell tumor (JCT, JGCT, also reninoma) is an extremely rare

kidney tumour Kidney tumours are tumours, or growths, on or in the kidney. These growths can be benign or malignant ( kidney cancer). Presentation Kidney tumours may be discovered on medical imaging incidentally (i.e. an incidentaloma), or may be present i ...

of the juxtaglomerular cells, with less than 100 cases reported in literature. This tumor typically secretes renin, hence the former name of reninoma. It often causes severe

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

that is difficult to control, in adults and children, although among causes of secondary hypertension it is rare. It develops most commonly in young adults, but can be diagnosed much later in life. It is generally considered benign, but its malignant potential is uncertain.

Pathophysiology

By hypersecretion of renin, JCT causes

, often severe and usually sustained but occasionally paroxysmal, and

secondary hyperaldosteronism Hyperaldosteronism is a medical condition wherein too much aldosterone is produced by the adrenal glands, which can lead to lowered levels of potassium in the blood ( hypokalemia) and increased hydrogen ion excretion (alkalosis). This cause of m ...

inducing hypokalemia, though the later can be mild despite high renin. Both of these conditions may be corrected by surgical removal of the tumor. Asymptomatic cases have been reported.

Histopathology

JCT is morphologically characterized by multiple foci malignant mesenchymal epithelioid cells with, often with admixed

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

, and a perivascular growth pattern. The immunophenotype is rather characteristic, as the neoplastic cells express renin, CD34, smooth muscle actin, CD138, vimentin, collagen IV and is negative for cytokeratins as well as for S100, c-Kit and desmin.

Diagnosis

Clinically,

, especially when severe or poorly controlled, combined with evidence of a kidney tumor via imaging or gross examination suggest a JCT. However, other kidney tumors can cause hypertension by secreting renin. JCTs have a variable appearance and have often being misdiagnosed as renal cell carcinomas; dynamic

computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

is helpful in the differential diagnosis. Post-operatively, the presence of renin granules in pathology specimens as well as immunohistochemical analyses could help differentiating this tumor from other primary renal tumors such as hemangiopericytoma, glomus tumor,

metanephric adenoma Metanephric adenoma (MA) is a rare, benign tumour of the kidney, that can have a microscopic appearance similar to a nephroblastoma (Wilms tumours), or a papillary renal cell carcinoma. It should not be confused with the pathologically unrelated ...

, epithelioid angiomyolipoma, Wilms tumor, solitary fibrous tumor, and some epithelial neoplasms.

Prognosis

JCT often is described as benign, however one case of metastasis has been reported, so its malignant potential is uncertain. In most cases the tumor is encapsulated.

History

Juxtaglomerular cell tumor was first described in 1967 in a paper by Robertson et al., and first named by Kihara et al. in 1968. Since then, approximately 100 case reports have been published. Karyotyping of a small number of these tumors revealed a common loss of chromosomes 9 and 11.

References

{{Urologic neoplasia Rare cancers Kidney cancer