Is whole-lung CT scanning still necessary in all cases of ACTH-dependent Cushing's syndrome in the era of petrosal sinus sampling?
We reviewed 31 patients in whom both bilateral inferior petrosal sinus sampling without CRH stimulation, and a CT scan of the lungs were done. Twenty-five had normal lung CT scans, of whom 23 had a higher inferior petrosal sinus: peripheral ACTH ratio > or = 1.5. After careful follow-up, none was subsequently shown to have ectopic ACTH syndrome. Six had abnormal lung CT scans, of whom two had ratios > or = 1.5. In these two patients, other investigations suggested pituitary disease, and pituitary surgery led to apparent cure. Of the remaining four patients, who had ratios < 1.5, two had incidental lung findings, and pituitary abnormalities were demonstrated at pituitary surgery. The third underwent bilateral adrenalectomy, and no evidence of ectopic ACTH syndrome has emerged as yet after 4 years follow-up. The fourth had a small-cell carcinoma of the lung, confirmed histologically. Our series suggests that whole-lung CT scanning is only necessary in cases of ACTH-dependent Cushing's syndrome where bilateral inferior petrosal sinus sampling has not demonstrated a significant increase in petrosal sinus ACTH levels as compared with the peripheral level. Thus, in our experience the test is now only necessary in those patients (approximately 25%) where the ratio is < or = 1.5.
Heaney
A
A
Sir George E. Clark Metabolic Unit, Royal Victoria Hospital, Belfast, UK.
Loughrey
G
G
McCance
D
D
McIlrath
E
E
Hadden
D
D
Kennedy
L
L
Sheridan
B
B
Atkinson
A B
AB
D000182:ACTH Syndrome, Ectopic / Q000175:diagnosis*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D015415:Biomarkers / Q000097:blood; D003480:Cushing Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000097:blood / Q000000981:diagnostic imaging*; D008297:Male; D017591:Petrosal Sinus Sampling; D014057:Tomography, X-Ray Computed
D015415:Biomarkers; D000324:Adrenocorticotropic Hormone