Crossing the other side of the algorithm: a challenging case of adrenal Cushing's syndrome.
The diagnosis of endogenous Cushing's syndrome and its aetiology involved documenting the hypercotisolism and then determining whether that hypercortisolism is adrenocorticotropic hormone-dependent (ACTH-dependent) or not. Hence, following the algorithm, an undetected ACTH level points to an adrenal Cushing's while a detectable or elevated ACTH level points to either a pituitary or ectopic Cushing's syndrome. The authors present a case of florid adrenal Cushing's syndrome initially presenting with a normal ACTH level, which led to the investigation for an ACTH-secreting tumour. Adding to the confusion, a MRI done showed an intrasellar focus. Knowledge of how ACTH-dependent (versus ACTH-independent) Cushing's syndrome manifests clinically, supported by results of repeat laboratory tests, led to the true diagnosis. This case illustrates that a detectable ACTH does not rule out an adrenal Cushing's syndrome nor does a positive pituitary imaging confirm Cushing's disease.
Department of Medicine, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines. imeemd777@yahoo.com
Imelda Digna Soberano
ID
Antonio
Mark Anthony Santiago
MA
Sandoval
Frances Lina
FL
Lantion-Ang
D000236:Adenoma / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000328:Adult; D000465:Algorithms; D003480:Cushing Syndrome / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011859:Radiography; D055815:Young Adult
D000324:Adrenocorticotropic Hormone