ACTH, as well as the deficiency in other pituitary hormones. An ectopic tumour secreting ACTH (A) can produce similar symptoms, however they usually originate from oat cell of small cell lung carcinomas which are associated with weight loss rather than headaches and visual disturbances. Iatrogenic steroid side effects (E) would cause symptoms imitating cortisol excess such as striae, bruising, thin skin and weight gain. A prolactinoma (B) can cause some of the symptoms the patient complains of, such as headache and visual disturbances, due to impingement upon surrounding structures. However, symptoms in males does not involve hyperpigmentation and usually include loss of libido, impotence and gynaecomastia. Addison’s disease (D) causes similar symptoms described in the question stem, however the cause of adrenal function loss is due to autoimmune action or infection.