6640 Utility of bilateral inferior petrosal sinus sampling for diagnosis and management of Cushing's disease in children ; a case report

Abstract Disclosure: V. leal: None. L. Socha: None. S.S. Awadalla: None. The causes of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS) are Cushing's disease (CD) and ectopic ACTH syndrome (EAS). The differential diagnosis of CS and the localization of lesions in CD and EAS are often challenging. The utility of bilateral inferior petrosal sinus sampling (BIPSS), an important test in adults, is less defined in children.A 16-year-old girl was referred for evaluation and treatment of Cushing syndrome she experienced weight gain, secondary amenorrhea, and back pain. 24-hour urinary free cortisol and low-dose dexamethasone suppression tests suggested Cushing syndrome. Adrenocorticotropic hormone (ACTH) level and high-dose dexamethasone suppression test confirmed Cushing disease. Pituitary magnetic resonance reported a microadenoma. To rule ectopic ACTH syndrome, and localize the pituitary tumor, bilateral inferior petrosal sinus sampling (BIPSS) was performed with desmopressin to stimulate ACTH. Finally, the patient was diagnosed with Cushing disease due to right ACTH-secreting pituitary microadenoma and underwent endoscopic endo-nasal transsphenoidal surgery.In conclusion , BIPSS can be a valuable tool not only for discriminating between pituitary origin and ectopic ACTH-secreting Cushing syndrome, but also for providing precise localization of pituitary adenomas, thereby facilitating appropriate treatment. Presentation: 6/1/2024