Endocrine Abstracts

Background: Neurofibromatosis type 1 (NF1) related Phaeochromocytoma is a rare endocrine disorder and diagnosis is frequently delayed. NF1 is frequently associated with gastro-intestinal stromal tumour but also reported with adenocarcinoma (rare genetic MLH1 mutation). We presented a case where diagnosis of phaeochromocytoma was delayed 5 years after initial symptoms and only incidentally found on scanning at the time of his presentation with colonic tumour.

History: A 67 year old part-retired farmer presented with altered bowel habits and bleeding per rectum. Subsequent colonoscopy and CT scan revealed an obstructing intussuscepting sigmoid colonic adenocarcinoma (histology confirmed). A heterogeneously enhancing 5 cm right adrenal mass was incidentally found on imaging. On detailed history revealed a 5 years history of hypertension and episodic classical symptoms – light headedness, blurred vision, feeling of impending collapse with pounding chest on straining or sheering sheep. This was previously investigated and diagnosed with vasovagal episodes. Clinically, he had multiple skin nodules presumed neurofibromatoma and axillary freckling. There was no café au lait spots.

Investigation: He had very high (>28 ULN) plasma normetanephrines 2,225 pmol/l and metanephrine 14,448 pmol/l. He was immediately started on alpha blockade and rapid dose titration, he is currently on low fibre diet with a preparation for surgery in a few weeks having a close collaboration with colorectal surgical, adrenal surgical and anaesthetic teams with a potential view of both procedures in one setting.

Discussions: Our patient’s diagnosis of phaeochromocytoma was missed despite having typical episodic symptoms, hypertension and neurofibromatoma. This case illustrates challenges of timing safety of anaesthesia (alpha-blockage) and potential untoward complication of delay of surgery for his colonic obstruction. It illustrated an importance role of very careful management in close collaboration with different teams. He is currently awaiting further genetic testing for probable neurofibromatosis type 1 (NF1) and a potential link of gastrointestinal cancer.