Uptake of exogenous estrogen as a differential diagnosis of ovarian-remnant-syndrome in a bitch: a case report

BACKGROUND: Clinical signs of heat in bitches that have been previously spayed are often associated with the presence of ovarian remnant syndrome. The inclusion of exogenous estrogens as a differential diagnosis in this regard is often ignored and may lead to misinterpretation of the case. CASE PRESENTATION: Herein, we report a case of exogenous estrogen exposure over several months to a 6.5-year-old spayed crossbred bitch, weighing 8.4 kg. The bitch presented in the clinic because of suspected ovarian remnant syndrome. Castration was performed within the first 6 months after birth. Important endocrine parameters measured at the first appointment were Anti-Müllerian hormone (< 0.01 ng/mL), progesterone (0.36 ng/mL), estradiol-17ß (20.7 pg/mL), and luteinizing hormone (< 0.1 ng/mL). After an extensive conversation with the owner, it was revealed that she was using an estrogen spray because of severe menopausal symptoms. After the owner stopped using this spray, the symptoms of the bitch disappeared. CONCLUSION: Therefore, the uptake of estrogens should be a differential diagnosis for symptoms of the ovarian remnant syndrome. A detailed anamnesis is crucial to identify the source of estrogen in the environment of the affected bitch.