Pulmonary neuroendocrine tumour-associated ectopic Cushing's syndrome: diagnostic challenges and multidisciplinary...

Ectopic adrenocorticotropic hormone (ACTH) secretion is a rare cause of Cushing's syndrome (CS), often associated with neuroendocrine tumours (NETs). Early diagnosis can be difficult due to variable clinical manifestations and psychiatric symptoms that may obscure the underlying endocrine disorder. We report a case of severe ectopic ACTH-dependent Cushing's syndrome secondary to a pulmonary NET, highlighting the importance of multidisciplinary management, advanced imaging with positron emission tomography/computed tomography with gallium-68-labelled DOTA-D-Phe-Tyr-octreotide (68Ga-DOTATOC PET-CT) and aggressive biochemical control to enable curative surgery and full clinical recovery.

Ectopic ACTH secretion should be suspected in cases of severe, rapidly progressive hypercortisolism with marked hypokalaemia. Combined therapy with metyrapone and ketoconazole, along with hydrocortisone blockade and replacement, allows for rapid and safe cortisol control before surgery. 68Ga-DOTATOC PET-CT is essential for accurate localisation and staging of neuroendocrine tumours with ectopic ACTH production. Multidisciplinary management involving endocrinology, nuclear medicine, radiology, psychiatry, nutrition and thoracic surgery is crucial for successful outcomes. Early identification and aggressive management of metabolic and psychiatric complications are key to full recovery.