An ACTH-secreting tumour hidden in a congenitally hypoplastic left lung.

Ectopic adrenocorticotrophic hormone (ACTH) syndrome has historically been a therapeutic challenge because of the difficulty localizing occult ACTH-secreting tumours. Here, we report a case of a 67-year-old woman with ectopic ACTH syndrome and had an ACTH-secreting tumour hidden within a congenitally hypoplastic left lung. A satisfactory therapeutic outcome was obtained after left pneumonectomy was performed on patient in this case.