Endocrine Abstracts

We report two cases of unilateral and bilateral phaeochromocytoma in patients with neurofibromatosis type 1 (NF-1) respectively.

Case 1

64 year old Caucasian male with known NF-1, hypertension, depression and osteoarthritis was referred with episodic symptoms of palpitation, chest pain and breathlessness. Biochemically confirmed phaeochromocytoma with 24 hr urinary metanephrines of 18595 nmol/24 hrs. CT revealed 4.2 cm right adrenal nodule and 2 cm left adrenal nodule. Both nodules showed increased uptake with MIBG. His BP was optimised with phenoxybenzamin initially and beta blockade later and had bilateral adrenalectomy followed by hydrocortisone and fludrocortisone replacement therapy. Histology confirmed bilateral phaeochromocytomas with complete resection and no atypical features. 24 hour metanephrines on follow-up were normal.

Case 2: 54 year old male with NF1 with a history of hypertension was found to have a 3.2 cm incidental left adrenal nodule while being investigated by Gastroenterology for weight loss. 24 hr urinary metanephrines were elevated to 3000 nmol/24 hrs. MIBG was in keeping with left pheochromocytoma. There was some evidence of increased uptake of MIBG on the right side, but CT did not reveal any nodules. He was managed pre-operatively with phenoxybenzamine and propranolol and underwent left laparoscopic left adrenalectomy with good recovery. Post-surgery urinary metanephrines were negative with no evidence of recurrence. He is being kept under review for the right side side.

Discussion: Neurofibromatosis-1 also called Von Recklinghausen’s disease has an autosomal dominant inheritance with complete penetrance and has an incidence of 1 in 3500.

Phaeochromocytoma has been clinically identified in 0.1–5.7% of patients with NF-1 and in 20–50% of NF-1 patients with hypertension, compared to 0.1% of all hypertensive individuals. Of the individuals with NF-1 and phaeochromocytomas, 9–27% have bilateral phaeochromocytomas. Bilateral phaeochromocytomas remain a rare manifestation of. In many cases, it presents with unilateral phaeochromoctoma with the other side developing it at a later stage. Screening for phaeochromocytoma should be a part of monitoring of people with NF-1 and particular attention should be paid to those with hypertension.