Endocrine Abstracts

Background: A 59 year old woman presented with recurrent symptoms of catecholamine excess (episodic headache and sweating). She was initially diagnosed in another centre to have a right adrenal phaeochromocytoma in 2002. She had suggestive symptoms, elevated urine catecholamines and a right adrenal mass on CT Adrenals. MIBG was however negative and they had proceeded with a right adrenalectomy and histology confirmed a phaeochromocytoma. She also had type 2 DM, anxiety and degeneratvive lumbar spine. In 2010 she presented to our centre with recurrent symptoms. Urine adrenaline was found to be elevated at 404 nmol/24h (Normal <100). CT abdomen revealed 16mm recurrent right adrenal mass but no uptake on MIBG. However PET scan shown mild metabolic activity in the nodule. Genetic screen didn’t find any known mutation for VHL1, SDHB, SDHD, RET, MEN 2, TMEM127 genes. The recurrent adenral mass was resected and histology shown benign phaeochromocytoma with lesion extending to excision marigins. Subsequent 24h urine metaadrenalins were normal. The patient started complaining of episodic recurrance episodic of her symptoms two years later and intermittently thereafter. However urinary and plasma catecholamines were within normal limits. Neurological investigations (MRI brain, CSF, EEG) didn’t reveal significant abnormality. In 2015 urinary collection shown new elevation of urinary meta-adrenaline at 1.96 (Normal <1.4) Repeat samples were similar after stopping amitryptyline. In March 2016 CT abdomen revealed a new 13x16mm nodule in upper pole of right kidney. However yet again in July 2017 SPECT CT MIBG images show no abnormal foci of uptake. Urinary meta-adrenaline elevated at 2.7. Phenoxybenzamine titration was commenced and she had resection in September 2017. Histology has shown incomplete excision of metastatic paraganglioma and she has expressed unwillingness for a fourth operative procedure. Subsequent urinary catcholamines and meta-adrenalines returned to normal level.

Discussion: This case illustrates the challenges in diagnostic process and identification of phaeochormocytoma and paraganglioma due to inconclusive functional investigations (MIBG and PET CT). Given incomplete excision further reoccurrence is very likely and there will be challenges ahead in choosing further surgical therapy(given her reluctance) and limitations in medical management options including 131I-mIBG therapy.