A patient with neurofibromatosis type-1 (NF1) presenting with multiple endocrine neoplasia (MEN)2B

Aung Mon; Nagaraj Malipatil; Dushyant Sharma; Rabia Aftab; Yee Koay; Pauline Whittingham; Amanda Hamilton; Jiten Vora

Background: NF1 and MEN2 are rare conditions known to associate with bilateral phaeochromochtomas. We describe, with relevant associated radiology, a NF1 patient developing a series of neuroendocrine tumours including bilateral phaeochromocytomas.

Clinical case: A 39-year-old lady presented with long standing episodic abdominal pain, diarrhoea, palpitation and sweating. Past history includes first arch syndrome and NF1 at teens and total thyroidectomy for the thyroid medullary carcinoma at age 31. Small bowel meal, fasting gut hormone profile, 24 h urinary catecholamines and 5 HIAA were normal. Abdominal CT scan revealed 2×1.5 cm mass in the right adrenal gland. Octreotide, meta-iodobenzylguanidine (MIBG) scan and Conn’s screening were normal. However, subsequent 24 h urinary dopamine levels increased. Urinary adrenaline and noradrenaline remained normal.

Repeat MIBG scan showed bilateral increased uptake in the supra-renal region indicating bilateral phaeochromocytomas. MRI adrenals showed a 2.5×1.7 cm mass at right adrenal. Adrenal venous sampling indicated left-sided phaeochromocytoma (Table).

	Left				Right
	Adrenal	Renal	Upper renal	Lower renal	Adrenal	Renal	Upper renal
Noradrenaline (normal<5.0 nmol/l)	127.6	15.2	12.3	1.6	3.9	5.7	9.0
Adrenaline (normal<1.0 nmol/l)	264	34.4	19.41	1.42	4.03	7.23	9.30

RET Proto-oncogene analysis on exons 10, 11, 13, 14, 15 and 16 was normal. Laparoscopic left adrenalectomy was carried out. However, post-operative MIBG scan showed increased uptake at the right adrenal region and adrenal venous sampling showed high gradient on the right adrenal vein which prompted right adrenalectomy. The histology from both adreanls confirmed composite phaeochromocytoma and ganglioneuroma.

MRI pituitary showed a microadenoma. Full dynamic pituitary function tests, calcium, parathyroid hormone and calcitonin levels were normal. Subsequent radiological investigations showed no interval changes.

Repeated genetic testing for exon-8 was consistent with likely MEN2B.

Conclusion: We present a patient with a rare combination of NF1 with MEN2B. The case also serves to illustrate the diagnostic and therapeutic challenges involved with MEN2B.

Endocrine Abstracts

P175