Cholesterol granuloma (Xanthomatous metritis) in the uterus of a cat

A case of uterine cholesterol granuloma in a 12-year old mixed breed cat is reported. The lesions were found in the endometrium of the left uterine horn as scattered, raised nodules or foci. Histologically, mononuclear cell infiltrates were seen to surround cholesterol crystals, in both the endometrium and the smooth muscle layer, reaching the serosa. The findings support the role of haemorrhage in promoting chronic inflammatory reactions around interstitial cholesterol ester precipitates.