Endocrine Abstracts

Introduction: NF1 or Von-Recklinghausen’s disease, an autosomal dominant neuro-cutaneous disorder results from NF1 (a tumour-suppressor gene) mutation, predisposing to neoplasms mainly affecting eye, skin and nervous system but rarely pheochromocytoma (0.1-5.7%). The incidence increases to 20-50% if NF1 is associated with hypertension.

Case history: 30 years female, known NF1 since 2005 and multiple laparotomies for intra-abdominal neurofibromas presented with abdominal pain and vomiting. No palpitations, headache, flushing or sweating. She was systemically and hemodynamically stable with systolic blood pressure ranging between 109-139 mmHg and heart-rate 69-101 beats/minute. Baseline investigations were normal but computed tomography of chest-abdomen-pelvis (CT-CAP) revealed multiple lesions as outlined. She was conservatively managed and discharged with endocrine follow up.

Investigations: Full blood count, bone, liver, renal and coagulation profile, amylase, C-reactive protein and short synacthen test were normal. Plasma Normetanephrine: 4773 pmol/l (<1180), Metanephrines: 2120 (<510), 3-Methoxytyramine 228 pmol/l (<180). Repeat Plasma metanephrines were also raised. CT-CAP: 42x35x34 mm heterogeneous mass, inseparable from the right adrenal gland, with intra-lesional necrosis besides several small soft tissue masses adjacent to right internal iliac vessels consistent with neurofibromata, 38x28x58 mm left-sided pleural based mass, a 20x37x22 mm subcarinal mass/lymph node and 38x23x32 mm soft tissue axillary mass. MRI Adrenals: Well-defined rounded lesion arising from the right adrenal gland with a clear fluid level representing relatively recent haemorrhage into a well-defined, likely benign, adrenal tumour.

Results and treatment: Underwent right adrenlectomy, biopsy confirming pheochromocytoma and plasma metanephrines normalized post-operatively.

Conclusions: 1. Pheochromocytoma with NF1 are rare but have significant morbidity and mortality if detected late therefore patients should be actively screened especially if associated with hypertension. 2. Pheochromocytoma can radiologically mimic intra-abdominal neurofibromas in patient with NF1 therefore caution must be considered. 3. Pheochromocytoma can present without classical symptoms of hypertension, tachycardia, flushing, sweating or headache so need high suspicion especially in NF1.