Tehran University Medical Journal

Background: Definite diagnosis and treatment of Cushing's syndrome is still a dilemma. The aim of this study was to evaluate the accuracy of diagnostic tests and follow-up of patients with Cushing's syndrome.
Methods: Two hundred and fifty three consecutive cases with Cushing's syndrome during 1370-78 were studied. The screening tests were performed in all patients. High dose dexamethasone suppression test (HDDST) and ACTH measurement were carried out. MRI/CT Scan were performed and compared with laboratory data and pathologic specimens as a gold standard test.
Results: The age range was 32±11 yrs. The most frequent symptoms were weakness hypertension, typical striae, and depression .The frequency of hypertension in ACTH-dependent case were 77% vs. 36% in adrenal tumors (P< 0.001). HDDST was positive in 99% of micro and 71% of macroadenomas. Adrenal tumors showed 3.6% suppression but none in ectopic cases. HDDST had a sensitivity of 98%, specificity of 97% and accuracy equals to 98%. The frequency of different etiologies was as following: Cushing's disease in 64.8%, adrenal tumors in 32.8% and ectopic ACTH in 2.4% of patients. Trans-sphenoidal surgery (TSS) was performed in 120 patients .The patients were followed for 53±25 months whose remission periods were 46.7±23.8 months (range 4-114 months). Survival analysis showed 93% remission rate in 12mo, 82% in 2yr and only 33% after 5yr.This recurrence didn't have any platue level.
Conclusion: In our study, hypertension was more prevalent in ACTH-dependent Cushing's syndrome. HDDST had acceptable sensitivity, specificity and accuracy. Lifelong follow up of pituitary adenomas is inevitable in the case of progressive and gradual nature of recurrence in these tumors.