RT Journal Article SR Electronic T1 Lesson of the month 2: An unusual cause of depression in an older man: Cushing’s syndrome resulting from metastatic small cell cancer of the prostate JF Clinical Medicine JO Clin Med FD Royal College of Physicians SP 432 OP 434 DO 10.7861/clinmedicine.18-5-432 VO 18 IS 5 A1 Paul Kleinig A1 Patrick Russell YR 2018 UL http://www.rcpjournals.org/content/18/5/432.abstract AB This article describes the case of an older patient whose main presenting problem was depression. A constellation of clinical and biochemical features led to a search for medical causes of his low mood, which uncovered ectopic adrenocorticotropic hormone (ACTH) secretion. Post-mortem examination showed that the source of ACTH was small cell neuroendocrine carcinoma of the prostate, and that the patient had died from the sequelae of profound immune suppression.