Juxtaglomerular cell tumour of the kidney: a rare cause of resistant hypertension

Summary Juxtaglomerular cell tumour (JGCT) is an unusually encountered clinical entity. A 33-year-old man with severe long-standing hypertension and hypokalaemia is described. The patient also suffered from polyuria, polydipsia, nocturia and severe headaches. On admission, laboratory investigation revealed hypokalaemia, kaliuresis, high aldosterone and renin levels, and the abdomen CT identified a mass of 4 cm at the right kidney. Kidney function was normal. Following nephrectomy, the histological investigation revealed the presence of a JGCT. Immunostaining was positive for CD34 as well as for smooth muscle actin and vimentin. Following surgery, a marked control of his hypertension with calcium channel blockers and normalization of the serum potassium, renin or aldosterone levels were reached. According to our findings, JGCT could be included in the differential diagnosis of secondary hypertension as it consists of a curable cause. The association of JGCT with hypertension and hypokalaemia focusing on the clinical presentation, diagnostic evaluation and management is herein discussed and a brief review of the existing literature is provided. Learning points Juxtaglomerular cell tumours (JGCT), despite their rarity, should be included in the differential diagnosis of secondary hypertension as they consist of a curable cause of hypertension. JGCT could be presented with resistant hypertension along with hypokalaemia, kaliuresis and metabolic alkalosis. Early recognition and management can help to prevent cardiovascular complications. Imaging (enhanced CT scans) may be considered as the primary diagnostic tool for the detection of renal or JGCT. For the confirmation of the diagnosis, a histopathologic examination is needed.

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

BackgroundJuxtaglomerular 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.MethodsIn 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.ResultsThe 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.ConclusionThe 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.

Phosphorylation of β1-integrin in juxtaglomerular cells helps control blood pressure during the progression of diabetic nephropathy

The induction of a high blood pressure due to diabetic nephropathy depends on the increase in renin secretion from juxtaglomerular cells, but many aspects of how juxtaglomerular cells sense blood pressure changes in the afferent arteriole and consequently react remain unclear. In this study, we detected the juxtaglomerular cell-specific phosphorylation of the threonine-788/789 site of β1-integrin, and its expression was negatively correlated with renin production. This relationship was also observed in a culture system of a juxtaglomerular cell line, suggesting that β1-integrin is deeply involved in the regulation of renin production. The knockdown of β1-integrin in the culture system increased renin production, but the degree of the increase was comparable to the increase in renin production by knockdown of connexin-40, which is considered to be an important molecule that plays a role in the pressure sensing mechanism of juxtaglomerular cells. This suggests that the mechanism underlying the regulation of renin production by β1-integrin in juxtaglomerular cells may contribute to the pressure-sensing function of juxtaglomerular cells themselves. Threonine-788/789 phosphorylation of β1-integrin may be involved in the regulation of this pressoreceptor function. (176 words)

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.