An Assessment of Petrosal Sinus Sampling for Localization of Pituitary Microadenomas in Children with Cushing Disease

Abstract

Pituitary adenomas in Cushing disease (CD) are usually small and difficult to visualize. Bilateral inferior petrosal venous sampling (BIPSS) before and after ovine CRH stimulation is reserved for patients who have ACTH-dependent Cushing syndrome and negative magnetic resonance imaging (MRI) or positive MRI but inconsistent biochemical data. The objective of the study was to evaluate the usefulness of BIPSS as a tool for localization of a pituitary adenoma in children with CD. The study was a retrospective review of the records of 141 children who were admitted for evaluation of CD from 1982 to 2004. The study was conducted at a tertiary care center. Lateralization of ACTH secretion during BIPSS was compared with MRI and surgical findings for the localization of a microadenoma. A total of 94 patients, 49 males and 45 females with an age range of 5.3 to 18.7 yr (13 +/- 3.2 yr), underwent BIPSS. Localization of a microadenoma by BIPSS agreed with surgical location in only 58% of the cases (95% confidence interval, 43-66). The combined use of information from the MRI and inferior petrosal venous sampling did not predict the location of the tumor more frequently than MRI alone (P > 0.1), which in this study localized a lesion in 39% of the patients (95% confidence interval, 28-50). The procedure was completed successfully in all patients, and no serious complications were recorded. Although BIPSS was safe and well tolerated in an experienced center, lateralization of the ACTH gradient during BIPSS was a poor predictor of the site of the adenoma in children with CD.