Objective: To analyze inferior petrosal sinus sampling (IPSS) in diagnosis and treatment of Cushing's disease with negative magnetic resonance imaging (MRI).
Methods: We retrospectively reviewed 79 cases of Cushing's disease with negative MRI in the Department of Neurosurgery of Peking Union Medical College Hospital from August 2012 to August 2014. Of the 79 patients, 58 underwent IPSS. There were 16 males and 42 females in this study, with age 12 to 65 years old. All 58 patients underwent endocrine assessment before transsphenoidal surgery, and pathology specimens were examined.
Results: The IPSS results of all the 58 patients suggested the excessive secretion of ACTH was from pituitary. Of the 58 patients, visible tumor was found in 56 cases during intraoperative exploration (96.6%). In 29 (50%) cases, the side of pituitary where tumor was located predicted by IPSS was the same with intraoperative exploration. Typical tumor was seen in 47 cases during exploration, and the endocrine remission rate was 83.0% after operation. Suspicious tumor was seen in 9 cases, and endocrine response rate was 44.4%. No tumor was found in two cases who had no remission after operation. Pituitary adenoma was confirmed in 41 patients (70.7%) by pathological exam. And anterior or posterior lobe of pituitary was reported in 12 cases, pituitary hyperplasia in 5 cases.
Conclusions: IPSS is recommended in Cushing's disease patients with negative MRI, and it is helpful to judge whether the excessive secretion of ACTH is from pituitary, while its value in predicting the lateralization of tumor is low. If IPSS results are positive, transsphenoidal surgery should be performed.