Phaeochromocytoma

•    Catecholamine-secreting tumour (usually adrenal medulla; 10% extra-adrenal)

•    Features: episodic headache, sweating, palpitations, hypertension (paroxysmal or sustained)

•    May be triggered by stress, surgery, β-blockers (unopposed α)

•    Diagnosis:

o    First-line: plasma metanephrines (high sensitivity)

o    Confirm with: 24h urinary catecholamines/metanephrines

o    Localisation: MRI or MIBG scan if not visible

•    Management:

o    Pre-op α-blockade (e.g. phenoxybenzamine) – always before β-blockade to prevent crisis

o    Then surgery (adrenalectomy)

Multiple Endocrine Neoplasia (MEN) Syndromes

MEN1 ("3 Ps")

•    Autosomal dominant mutation in MEN1 (menin) gene

•    Tumours of:

o    Parathyroid (hyperparathyroidism – most common)

o    Pituitary (prolactinoma, GH adenoma)

o    Pancreas (gastrinoma, insulinoma, VIPoma)

•    Screen: calcium, PTH, prolactin, gastrin

MEN2A

•    Mutation in RET proto-oncogene

•    Tumours of:

o    Medullary thyroid carcinoma (MTC)

o    Phaeochromocytoma

o    Parathyroid hyperplasia

•    Prophylactic thyroidectomy advised in RET-positive individuals

MEN2B

•    Also RET mutation (different codon from MEN2A)

•    Features:

o    MTC

o    Phaeochromocytoma

o    Marfanoid habitus

o    Mucosal neuromas (e.g. tongue, lips, eyelids)

•    More aggressive MTC than MEN2A