An 8-year-old, crossbred domestic queen, weighing 2.9 kg, was examined because of obvious clinical signs, including anorexia, lethargy and vomiting, with small quantities of yellow vaginal mucopurulent discharge. Palpation revealed the presence of an abdominal mass. A diagnosis of pyometra was made by radiology. After undergoing ovario-hysterectomy, the queen made a full recovery. Histopathological examination of the uterus and ovary was made. A sterilization case was included for microscopic comparison. Results showed that endometrium of the cat with pyometra presented atrophy and shedding of superficial epithelium, and there were apparent cystic follicles in ovary.

Key words: Cat, Histopathology, Ovary, Pyometra, Uterus