Renin-secreting juxtaglomerular tumor causing severe hypertension: diagnosis by computerized tomography-directed needle biopsy

Renin-producing Tumour in the Kidney of a Cat

Clinical and post-mortem examination of an adult neutered male cat with immune-mediated haemolytic anaemia revealed suspected nodules of tumour tissue in the cortex of the right kidney. Cytology and histopathology indicated a malignant renal tumour of undetermined type. Immunohistochemistry confirmed renin production by a proportion of the tumour cells. The lesion may represent a renal adenocarcinoma producing renin or a tumour of juxtaglomerular cells ('reninoma').

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.

[Renin-secreting tumour: about a new diagnosed case during pregnancy]

A 29 year-old female patient developed severe arterial hypertension in the beginning of her second pregnancy. Investigations performed at 16 weeks of amenorrhea showed hypokaliemia in relation to severe hyperreninism: plasma active renin was 25 fold normal value, 94% as prorenin (prorenin representing 94% of total renin). Radiological investigations including ultrasonography and MRI disclosed an homogenous and avascular tumor in the right kidney. Its ablation confirmed renin tumor, and allowed recovery from HTA and continuation of pregnancy. This is the 75th reported case in the literature, enabling to make a new statement about diagnostic and therapeutic procedures, which are modified during pregnancy by contra-indication to X-rays and renin-angiotensin-aldosteron axis inhibitors.

Reninoma treated with nephron-sparing surgery

A 14-year-old hypertensive boy was evaluated in our clinic. The physical examination was essentially normal except for his high blood pressure. Laboratory findings showed increased plasma renin activity. Abdominal ultrasonography detected a hypoechoic, 2-cm mass in right kidney. Contrast-enhanced computed tomography of the abdomen revealed a well-circumscribed, solid, hypoenhancing cortical lesion in the middle of the right kidney. Magnetic resonance angiography documented bilateral normal renal arteries. With a preoperative diagnosis of reninoma, the patient underwent nephron-sparing surgery. Intraoperative frozen section analysis revealed a benign lesion. Subsequently, histopathologic examination and electron microscopy confirmed the diagnosis of juxtaglomerular cell tumor. The patient remained normotensive in the postoperative period. Follow-up intravenous urography showed bilateral normally functioning kidneys.

Adult-onset giant juxtaglomerular cell tumor of the kidney

The juxtaglomerular cell tumor (JGCT) of the kidney is a rare neoplasm which commonly secretes renin. This tumor often occurs in teenagers. This paper documents the 14th adult-onset (over 30-years-old) case with a giant JGCT which measured 9.0 x 8.0 x 7.5 cm. Histologically, this tumor was composed of both vascular and tubular components. Immunohistochemically, the vascular component reacted with renin, cytokeratin 7, ulex europaeus agglutinin-1, vascular endothelial growth factor (VEGF) and Flk-1 (VEGF-R2), whereas the tubular component was positive for renin, epithelial membrane antigen (EMA), cytokeratin 7, alpha-1-antitrypsin, VEGF and Flk-1. This finding suggests that both vascular and tubular components of JGCT may promote neoplastic proliferation via an autocrine mechanism through the action of VEGF.

Renin secreting tumors: diagnosis, conservative surgical approach and long-term results

During the last 15 years 8 patients were diagnosed with renin secreting juxtaglomerular cell tumors among 30,000 hypertensive patients. Clinical characteristics included severe hypertension poorly medically controlled in young patients (mean age 22.3 years) and severe hypokalemia (mean 2.83 mmol./l.). Secondary hyperaldosteronism was present in all cases with a constant elevation of renin activity. Renal vein sampling was only positive in 64% of cases. Selective renal arteriography demonstrated an avascular area in 43% of the patients. Computerized tomography showed the tumor in all cases. Mean tumor size was 24 mm. (range 10 to 50). Conservative surgery was feasible in all patients. Perioperative ultrasonography was used for 3 intraparenchymal tumors. Hypertension and hypokalemia resolved within 1 week after surgery. At a mean followup of 98 months (range 24 to 204) no tumor recurrence was documented.