IMPROVED DIAGNOSTIC-ACCURACY OF INFERIOR PETROSAL SINUS SAMPLING OVERIMAGING FOR LOCALIZING PITUITARY PATHOLOGY IN PATIENTS WITH CUSHINGS-DISEASE

The majority of patients with Gushing's disease can be cured by transs phenoidal microsurgery; however, precise localization of the pituitary source of ACTH is not always possible by standard imaging techniques. Bilateral venous sampling from the inferior petrosal sinuses (IPSS) i s also useful for diagnosing Gushing's disease, but the interpretation of discordant findings between IPSS and imaging remains problematic. We tested the ability of imaging and IPSS to localize an ACTH-secretin g pituitary lesion in comparison to definitive histopathological exami nation of the pituitary in patients with Gushing's disease (n = 37). B ilateral IFS catheterization was technically feasible in 32 patients a nd provided evidence of lateralization in 31 patients. Histological ex amination confirmed a corticotropic adenoma in 28 patients and cortico tropic hyperplasia in 2 patients; Crooke's hyaline change was found in 7 patients, among whom 1 subsequently was found to have an ectopic sp henoid corticotropic adenoma, and the remainder had suspected microade nomas that were not identified microscopically. Accurate localization of the pituitary lesion was more frequent when based on IPSS results t han on imaging studies (70% vs. 49%, P < 0.06). The 2 tests provided d irectly discrepant results for 8 patients; among these, IPSS was more likely than imaging to agree with final pathology (63% vs. 13%, P < 0. 10). Imaging was entirely normal for another 9 patients, in whom IPSS accurately localized the lesion for the majority (89%; 95% confidence interval: 50-99%). We suggest that IPSS is an effective tool for local izing pituitary pathology and planning surgery for patients with Gushi ng's disease.