Petrosal sinus sampling in the diagnosis of Cushing's syndrome: preliminary experience in University of Malaya Medical Centre.

Differentiating between Cushing's disease of pituitary origin and ectopic ACTH syndrome of extra-pituitary origin remains a major challenge to the clinician because of limitations in the diagnostic accuracy of the high-dose dexamethasone suppression test. Routine use of inferior petrosal sinus sampling (IPSS) is therefore advocated by some authors for these patients. We present our preliminary experience of IPSS in 7 consecutive patients with Cushing's disease and discuss how the results impacted on the patients' management.