Cystic endometrial hyperplasia-pyometra complex in the bitch: Should the two entities be disconnected

The uteri of 26 clinically healthy bitches and 42 bitches with a clinical s uspicion of pyometra were examined histologically using a computerized imag e analysis system. Histologic lesions were characterised mainly by thickeni ng or atrophy of the endometrium and by varying degrees of cystic changes o f the glands. These lesions were observed in most of the clinically healthy bitches as well as in all of the clinically ill animals. In most of the il l bitches a variable degree of inflammation also was found. Some bitches wi th clinical signs indicative for pyometra had no inflammatory reaction in t he uterus. These bitches were misdiagnosed as suffering from pyometra, conf irming the difficulty of diagnosing pyometra by simple clinical examination . Determination of sex hormone serum levels revealed that all dogs in both groups were either in metestrus or in anestrus. Based on the results of this study the cystic endometrial hyperplasia-pyome tra complex can be divided in two entities: a cystic endometrial hyperplasi a-mucometra complex and an endometritis-pyometra complex. Both entities bea r many similarities with each other, except for the inflammatory reaction i n the endometritis-pyometra complex. It is concluded from this study that t he latter complex probably does not necessarily follow the former, but that both can anise de novo. (C) 2001 by Elsevier Science Inc.