Abstract
Endometrial polyps from an 11-year-old female nulliparous mongrel cat are described. Pedunclated polypoid masses consisting mainly of endometrial glands and stroma protruded into the lumen of the uterus. The endometrial glands were distributed in a haphazard low density pattern, while the stromal cells were distributed with various consistency. Throughout the polyps, mild to moderate proliferation of the connective tissue with admixed small blood vessels was observed, with some of these blood vessels exhibiting thickened walls. The perivascular stromal element was also observed in polyps, as an incidental microscopic finding. It was characterized by multiple perivascular whorl-like arrangements of spindle shaped cells. They were immunohistochemically positive for alpha-smooth muscle actin, desmin, and S-100. These elements appear to originate from the endometrial stromal cells through smooth muscle metaplasia.
