Ectopic ACTH secretion from a metastatic gastric carcinoma with neuroendocrine component.

An elderly gentleman was admitted to hospital with severe hypokalaemia of 1.75mmol/L. A background of a recently diagnosed metastatic gastric carcinoma with a neuroendocrine component pointed towards the diagnosis of ectopic ACTH secretion causing this dangerous electrolyte imbalance. He was treated with aggressive potassium supplementation and the adrenal steroid synthesis blocker metyrapone to acutely control his Cushing's syndrome. Chemotherapy consisting of carboplatin/etoposide combination was initiated but unfortunately the patients' health deteriorated, and he died three months after his initial diagnosis. This case highlights the accelerated presentation of hypercortisolism due to ectopic ACTH secretion. It discusses the classification of neuroendocrine tumours and their varied prognosis depending on the underlying tumour grade. It emphasises the importance of having a multidisciplinary team to be able to care for two underlying pathologies simultaneously: both the severe hypercortisolism and his metastatic gastric tumour.