Endocrine Abstracts

Background: Von Hippel-Lindau (VHL) is a genetic syndrome caused by mutations in the VHL tumour-suppressor gene, that predisposes individuals to CNS and retinal haemangioblastomas, pheochromocytomas, neuroendocrine tumours of pancreas, renal and pancreatic cysts and other benign tumours. VHL may initially present subtly, but early recognition is essential to prevent serious complications and guide lifelong follow-up.

Case: A 32-year-old man was referred to Ambulatory Care Unit with 6-month history of recurrent headaches, palpitations, and persistent high blood pressure despite ramipril 5 mg once daily. He also reported intermittent episodes of flushing and sweating lasting 10–15 minutes, often triggered by stress or exertion. On examination, the blood pressure was 180/110 mmHg and the resting heart rate was 110 bpm. No other abnormalities were noted on physical examination. There was no evidence of end-organ damage. Serum electrolytes, PTH, renal/liver/thyroid function, cortisol and renin/aldosterone ratio were all within a normal range. However, plasma-free metanephrine was significantly elevated at 2.5 nmol/l (normal <0.5), as was normetanephrine at 3.8 nmol/l (normal <0.9). MRI of the abdomen revealed a 4 cm right adrenal mass in keeping with a pheochromocytoma, along with incidental pancreatic and renal cysts. MIBG scintigraphy showed a high accumulation of the tracer in the right adrenal lesion. MRI brain and spine showed multiple posterior fossa haemangioblastomas. Fundoscopy showed no abnormality. A detailed family history revealed that patient’s father died in his 40 s from a brain tumour. The patient was started on alpha-blockade with phenoxybenzamine for blood pressure control prior to surgery. Once adequate alpha-blockade was achieved, a beta-blocker was added. He subsequently underwent laparoscopic adrenalectomy without complications. Postoperatively, blood pressure normalised and his episodes of flushing and palpitations resolved. Patient was referred to the neurosurgical team for an assessment for the CNS haemangioblastomas. He was started on prednisolone for headaches and was offered a neurosurgical intervention. Genetic testing confirmed a pathogenic VHL mutation. On discharge, he was enrolled in a structured surveillance program including periodic MRI scans of abdomen, brain and spinal cord, regular eye exams by ophthalmologist, regular bloods for plasma metanephrines and urine for catecholamines. First-degree relatives were offered genetic counselling and testing.

Discussion: This case demonstrates that hypertension in young adults can rarely be a clue to an underlying hereditary tumour syndrome. Pheochromocytomas may present subtly- a careful analysis of symptoms, biochemistry and imaging is essential for diagnosis.