Endocrine Abstracts

Case history: 52 year old gentleman presented in 2013 with a 1 year history of abdominal pain. Imaging to screen for gallstones identified a large adrenal mass which was radiologically suspicious for adrenal carcinoma with probable inferior vena cava (IVC) involvement.

Investigations: Overnight dexamethasone suppression test (ONDST) failed to suppress cortisol (324 nmol/l) with undetectable ACTH (<5 ng/l). Failure of suppression on low dose dexamethasone suppression test (cortisol [nmol/l]: T=0, 324; T=48h, 286; ACTH [ng/l]: T=0, <5; T=48h, <5) confirmed a cortisol-producing tumour. Urinary fractionated metanephrines were 2.46 umol/24h (normal <3.47), ruling out phaeochromocytoma.

Results and treatment: A 28 cm right adrenal tumour was resected en bloc with a section of IVC and partial hepatectomy. Recovery was complicated by post-operative cardiac arrest and prolonged ITU stay. Histopathology was suggestive of a malignant tumour with Weiss score of 9, with viable tumour confirmed in the main adrenal vein/IVC. Post-operatively the patient required steroid replacement due to contralateral adrenal suppression. Short synacthen test (SST) showed cortisol 130 (T=0 m), 129 (T=30 m) and 136 (T=60 m). In view of the high risk of recurrence the patient was offered post-operative mitotane therapy which he has consistently declined, so has been followed up with clinical, biochemical and radiological monitoring. ONDST has consistently suppressed cortisol fully (<20), however, the patient developed Cushingoid features with weight gain and hypertension. Serial cross-sectional imaging has shown no evidence of macroscopic disease recurrence at 5 years post-resection. Since 2015, 24-hour urine collection has shown elevated adrenal androgens and cortisol metabolites suggestive of adrenal Cushing’s, presumed secondary to microscopic disease not visible on imaging. He remains steroid-dependent on replacement prednisolone. Most recent SST showed baseline ACTH 92.8, cortisol 214 (T=0 m), 246 (T=30 m) and 244 (T=60 m).

Conclusions: Case series suggest very poor prognosis for large adrenocortical carcinomas with vascular invasion at presentation, and routine management would involve post-operative mitotane for this reason. However, there is a risk of selection bias in case series from tertiary referral centres, as advanced disease may prompt referral. Our patient declined conventional therapy but remains free of macroscopic disease recurrence at 5 years. He appears to have active cortisol precursor production causing elevated urinary metabolites and Cushingoid features, but persistently suppressed peak cortisol on SST and fully suppressed cortisol on ONDST. Mindful consideration is given to achieving ACTH suppression with steroid replacement to reduce the risk of overt disease recurrence, balanced against the adverse metabolic effects of rendering him Cushingoid.