I. Spontaneous Chromophobe Pituitary Tumors*

Tumors of the pituitary make up approximately 7 per cent of the intracranial neoplasms of man (61). As isolated cases they have been found in the horse (41, 48), dog (29, 37), cow (1), deer (53), Indian buffalo (16), baboon (25), and mouse (@3, 54). Following the description by Olga Fischer of large hypophyseal adenomas in two old rats (15), several investigators have reported a high mci dence of these tumors in rats of advanced age (1@, 40, 46, 47, 59, 60). Only two instances of reported pituitary tumors in animals other than mammals are known to the writer. One was seen in an African parakeet Agapornis pullaria by Slye (54); the second,a chromophobeadenomain an aquarium fish Lebistes reticulatus, was recently described by Stolk (55). The absence of additional reported cases in the lower vertebrates is par ticularly striking among the birds where thousands of chickens, ducks, turkeys, and geese are autop sied yearly by veterinary pathologists (27). This report is based on a study of 50 parakeets with pituitary tumors. . The investigation was undertaken after a bird brought to the writer by Dr. Jerome Rini proved to have such a lesion and when a cursory examination of several flocks had revealed the prevalence of the tumor (50). The cases presented are unselected and represent the first 50 pituitary neoplasms examined in this laboratory.