To investigate the clinical features and pathological classification of patients with nonfunctional pituitary adenomas(NFPAs)in single medical center according to 2017 World Health Organization.

The clinical and pathological characteristics of 166 patients with NFPAs diagnosed by neurosurgery in Peking Union Medical College Hospital from April 2019 to January 2020 were analyzed retrospectively.

In 166 patients, the ratio of male to female was almost equal(1.05∶1). Their average operation age was(49.9±12.3) years, which was significantly higher than that of functional pituitary tumor patients in the same period. Headache, visual acuity decline, and visual field defect were the most common causes for the first visit. All the maximum diameter of tumors was more than 10 mm, and 15 cases(9.0%)were giant tumors. 18 patients(10.8%)were recurrent cases. According to the results of immunohistochemistry for anterior pituitary hormones and transcriptional factors, the most common pathological type was gonadotroph adenomas(50.6%), followed by corticotroph adenomas(24.7%), plurihormonal pituitary adenomas(11.4%), PIT-1-positive adenomas(6.6%), and null cell adenomas(6.6%). Gonadotroph adenomas were more common in men(male∶female ratio=4.1∶1), while corticotroph adenomas occurred mainly in women(male∶female ratio=1∶12.7). The average age of patients with gonadotroph adenomas was the highest, while those of patients with PIT1-positive adenomas and rare combining IHC plurihormonal pituitary adenoma were significantly lower than that of the former. There were no significant differences in the mean diameters of tumors, the proportion of giant adenomas, and recurrent cases among different pathological types of tumors. However, the mean Ki-67 index of PIT-1-positive adenomas was significantly higher than those of other groups(P=0.001).

Although the clinical manifestations of NFPAs were similar, their pathological classifications were different. Gonadotroph adenomas occurs mainly in male patients while corticotroph adenomas is more common in women. The prognosis may be different among various pathological types of NFPAs.

Nonfunctioning pituitary adenoma; Disease characteristics; Pathological classification