Endocrine Abstracts

We present 2 cases of extraadrenal phaeochromocytoma with several unusual features: (a) A 54 year-old female presented with dizziness, falls, and palpitations. She was tachycardic with blood pressure of 218/75 supine and 139/107 standing. An abdominal mass was palpable. Urinary catecholamines were markedly raised and a CT scan showed para-aortic mass with avid MIBG uptake confirming the diagnosis of an extraadrenal phaeochromocytoma. Persistent hypokalaemia and hyperglycaemia raised suspicion of hypercortisolism. High plasma cortisol (>1750 nmol/l) failed to suppress after low and high doses of dexamethasone and 9 am ACTH was high at 913 pmol/l (N<46 pmol/l). Results were suggestive of ectopic ACTH production and the phaeochromocytoma was considered to be the source. Following pre-operative metyrapone and α+β blockade, tumour was resected and histology confirmed the clinical diagnosis. Postoperatively urinary catecholamines normalised and all medications were weaned off over next 4 weeks. Synacthen test showed normal response. ACTH immunostaining was negative suggesting the possibility of ectopic CRH secretion. To our knowledge this is the first report of an ACTH/CRH secreting extraadrenal phaeochromocytoma.

(b) A 27-year old man presented with a 14-year history of paroxysmal headaches and palpitations precipitated by mictuirition. He was hypertensive and tachycardic. Urinary catecholamines were markedly elevated. MRI identified a paravesical mass and pelvic lymphadenopathy with significant MIBG uptake diagnostic of locally metastatic extra-adrenal phaeochromocytoma. Following pharmacological preparation he underwent excision of primary lesion, partial cystectomy and nodal clearance. Post-operatively urinary catecholamines remained elevated. MIBG scan failed to confirm residual disease. However a PET scan revealed widespread distant metastases precluding further surgery. MIBG-labelled radiotherapy is being considered. This case illustrates several interesting features including early onset of symptoms in absence of family history or endocrine syndromes, failure of pre- and post-operative MIBG scan to identify distant metastases and usefulness of PET in evaluation of such cases.

In conclusion, phaeochromocytomas often have varied presentation requiring high index of clinical suspicion and systematic localisation. Delayed diagnosis can cause severe morbidity and reduced life span.