Rare mixed uterine teratoma with ovarian involvement in a Labrador Retriever dog

Abstract This case is a unique co‐presentation of mixed uterine and ovarian teratoma in a middle‐aged female Labrador dog with chief complaint of purulent vaginal discharge. On ultrasonographic examination, a large anechoic mass with several echogenic flakes in uterine lumen and cystic cavitation of endometrial surface was identified without any metastasis on radiography. After 2‐week medicinal therapy, ovariohysterectomy of dog was done and pyometra with large greyish white globoid soft fibroid mass (8.5 × 9.5 cm) on anterior border of right uterine horn formed remarkable findings. The histopathological analysis revealed stratified squamous metaplasia of endometrial epithelium with strong epidermal reaction pattern, in addition to, indistinct areas of degenerated hair follicle(s) and melanin deposits, areas of irregular, aggressive neuro‐fibromatous stroma, amidst muscular stroma turned fibrous and adipose connective tissues component. The dog recovered uneventfully. Therefore, we report rare case of mixed uterine and ovarian teratoma along with cystic endometrial hyperplasia‒pyometra complex in dog.