Endocrine Abstracts

Introduction: Just-glomerular tumours (reninomas) are rare causes of secondary hypertension (HT). They typically present with difficult to manage-HT, hypokalemia, hyperreninemia and secondary hyperaldosteronism. They are usually small lesions (<1 cm) and are more common in adolescents or young adults. Despite being rare, they should be considered in the diagnostic approach of secondary HT, as it they are a potentially curable cause.

Case report: Female patient, 45 years old, with personal history of difficult to manage-HT associated with hypokalemia since age 35, medicated with perindopril/amlodipine, metoprolol and spironolactone. She was sent to our department and, after suspension of spironolactone and correction of hypokalemia, we confirmed secondary hyperaldosteronism, with aldosterone of 44.3 ng/dl (4–28 ng/dl) and renin>1000 mIU/ml (4.4–46.2 mIU/ml). She performed an abdominal CT, which identified a heterogeneous nodule located in the middle third of the right kidney, with 37 mm; renal arteries had normal diameter. Partial nephrectomy was performed afterwards and histological analysis confirmed the diagnosis of reninoma, with 27 mm of diameter. After surgery, the patient had normal levels of aldosterone (9.2 ng/dl) and renin (1.20 mIU/ml). She remains without any antihypertensive medication and underwent an ambulatory blood pressure monitoring for 24 h, which confirmed the normalization of blood pressure.

Conclusion: Reninomas are very rare tumours and a potentially curable cause of endocrine hypertension. They are usually benign and its diagnosis should be considered in patients with difficult to control-HT, hypokalemia and secondary hyperaldosteronism, in whom renovascular or parenchymal disease has been excluded. In this case, considering the surgical indication proposed by the urologist regardless of the tumor’s functional behavior, the high clinical suspicion and the patient’s comfort, we chose not to suspend the antihypertensive medication, except for spironolactone. Surgical resection of the tumor is the treatment of choice and leads to normalization of blood pressure.