Biologic Behavior of Canine Mammary Neoplasms Based on a Histogenetic Classification

Abstract

Out of more than 1,200 bitches with mammary neoplasia 154 were selected to evaluate the biologic behavior of their neoplasms, based on an acceptable follow-up record and terminal examination. The 271 neoplasms were placed in 11 categories on the basis of histogenesis. Twenty-eight (18%) of the bitches were placed in more than one category to evaluate the behavior of their multiple neoplasms. There were distinctive differences in biologic behavior of the various categories. Infiltrating ductular carcinomas had a shorter duration after diagnosis than did any of the other neoplasms, particularly the benign ones and the in situ carcinomas. The average duration prior to diagnosis was similar in most neoplasms, except for ductular carcinomas in mixed tumors and intraductal papillomas, which had a longer duration. Papillary ductular carcinomas had a shorter duration both before and after diagnosis than did either the solid (or variable) ductular carcinomas or the scirrhous ductular carcinomas, indicating that classification according to histologic type is valuable in at least the ductular carcinomas.