A rare case of vulvar discharge associated with exogenous oestrogen exposure in a spayed Weimaraner bitch

OBJECTIVE: This report documents a rare case of vulvar discharge associated with exogenous oestrogen exposure in a large‐breed dog. CASE DESCRIPTION: A 4‐year‐old spayed Weimaraner bitch was presented for evaluation of inappetence and intermittent sanguineous vulvar discharge. Physical examination, vaginal cytology, haematological, and ultrasonographic findings were indicative of a uterine stump pyometra. A celiotomy was performed, and the uterine stump appeared grossly cystic and thickened. Histopathological evaluation of the removed uterine stump and ovarian pedicles revealed cystic endometrial hyperplasia and no ovarian tissue. Fifteen days after surgery, the patient presented again with a sanguineous vulvar discharge. Vaginal cytology revealed predominantly superficial cells, indicating oestrogen influence. Further questioning of the owner revealed the long‐term use of a topical oestrogen cream by a member of the household. Serial examinations were performed, and the cytology remained uniform, with predominantly superficial cells, indicating continued oestrogen influence. Progesterone and anti‐Müllerian hormone tests were negative, which made the presence of ectopic ovarian tissue unlikely. These results coupled with the history of topical oestrogen cream use in the household suggested that the patient's clinical signs were most likely due to exogenous oestrogen exposure. After the owner implemented various recommendations made to prevent the exposure, the clinical signs resolved completely. CONCLUSIONS: This case demonstrates that although rare, exogenous oestrogen exposure can be a cause of vulvar discharge in a large‐breed spayed bitch. Therefore, regardless of the breed, exogenous oestrogen exposure must be included in the list of differential diagnoses for all clinical presentations associated with oestrogenic influence in dogs.