Endocrine Abstracts

Coexistence of Acromegaly with Cushing’s syndrome in the same individual is rare. We herein describe a case of a 59-year-old woman, whose hypercortisolism was unmasked following transphenoidal surgery for Acromegaly.

She presented to the Endocrine Clinic in 2006 with acromegalic features and MRI revealing a pituitary macroadenoma 20×18×18 mm. Repeat dynamic evaluation showed inadequate GH suppression (initially normal), raising the possibility of early rumbling Acromegaly. 0900 hrs serum cortisol was 287 nmol/l. She was started on Cabergoline, later switched to Lanreotide but underwent transphenoidal surgery in 2015 due to evolving visual defects. Histology revealed a sparsely granulated somatotroph adenoma, ACTH negative with Ki67<1%. Postoperative serum cortisol was noted >1000 nmol/l on discharge.

A month later, she attended outpatients with typical Cushingoid facies, new onset diabetes mellitus, hypertension with severe hypokalaemic alkalosis and significant proximal myopathy and was admitted acutely. Random serum cortisol >2000 nmol/l, with failure to suppress on overnight, low and high dose dexamethasone suppression. ACTH was elevated at 118 ng/l. She was initiated on Metyrapone and Octreotide with clinical improvement a few days later. Repeat MRI pituitary revealed significant residual pituitary tumour burden with new bilateral avid adrenal hyperplasia on FDG-PET (normal 6months earlier), with persistent incidental non FDG-avid lung and thyroid lesions. She unfortunately became septic whilst awaiting transfer to the local tertiary centre and died from a stroke.

This case highlights the rare coexistence of two endocrine pathologies with Cushing’s syndrome being unmasked following discontinuation of Lanreotide and the importance therewith of close endocrine surveillance in postoperative pituitary patients in the acute, medium and long-term phases. Prompt early management of active Cushing’s is imperative to minimize significant morbidity and mortality. The true source of her excess ACTH causing hypercortisolism (pituitary or ectopic) remains a discussion point as post-mortem findings were inconclusive.