Only a few references have been made in the literature concerning hypophyseal tumors in domesticated animals. Nieberle states that tumors of the hypophysis may occur in domesticated animals, and that adenomas are the predominating type. He does not give any indication, however, where these tumors are more fully described, nor in what species they occur. It is because of this situation that the authors feel a description of a fibroma involving the pituitary of a fifteen year old Boston Terrier would be highly beneficial to report.