3 cases of ectopic ACTH pituitary adenoma and literature review

Objective To evaluate the clinical and laboratory features of 3 cases of ectopic ACTH pituitary adenoma (EAPA). Methods 3 cases of EAPA confirmed by surgery and pathological,examination have been retrospectively investigated in Peking Union Medical College Hospital since 1994.There were 2 female and 1 male patients with age ranging between 17 ～ 22y. The relevant literatures of EAPA were reviewed.Results The level of plasma ACTH was 126 ～ 207 pg/ml.The result of high dose dexamethasone suppression test was not suppressed in 1 case. The localization of EAPA tumor was suprasellar in 2 cases and left cavernous sinus in lcase. The results of inferior petrosal sinus sampling (IPSS) showed the ratio of inferior petrosal sinus (IPS):Peripheral (P) of plasma ACTH was 10.26 for 1 case with suprasellar EAPA and ＜ 2 for the other 1 case with left cavernous sinus EAPA.The pathological examination confirmed the diagnosis of EAPA with positive immunohistochemical staining of ACTH for all 3 cases after operation.The level of plasma ACTH and urine free cortisol decreased obviously after operation.Conclusions EAPA should be considered in the differential diagnosis for all patients with Cushing 's syndrome.The diagnosis and treatment of EAPA tumor are both difficult to carry out.IPSS may be helpful for the diagnosis of EAPA. Key words: Cushing syndrome; Cushing disease; ACTH syndrome, ectopic; Petrosal sinus sampling