Arrhenoblastoma in a mare.

This research article discusses a case report where a type of ovarian tumor (arrhenoblastoma) was found and surgically removed in a 14-year-old Appaloosa mare. The study highlights the mare’s behavioral changes leading to the discovery of the tumor and the associated hormonal changes.

Identification of the Problem

• The paper begins with the recognition of a behavioral issue exhibited by a 14-year-old Appaloosa mare. For 2 years, the mare had been acting aggressively towards other broodmares.
• This behavioural change provided the initial signal that there might be an internal problem with the mare. Aggression in mares can be linked to hormonal imbalances or physical ailments.

Ovarian Neoplasm Discovery and Diagnosis

• Upon veterinary exploration, an ovarian neoplasm (tumor) measuring 10 by 8 by 6 cm was discovered. This large tumor was surgically removed from the mare.
• The tumor was histologically diagnosed as an arrhenoblastoma. Arrhenoblastoma is a rare type of ovarian tumor that often leads to the production of male sex hormones, explaining the mare’s aggressive behaviour. The behavior changes were likely due to the hormonal changes caused by the tumor.

Preoperative Endocrinologic Findings

• The diagnosis of arrhenoblastoma was further supported by pre-surgery endocrine findings. The researchers tested the mare’s serum and found high concentrations of testosterone and low concentrations of estradiol.
• These hormone levels are not typical for a female horse, further suggesting the existence of the arrhenoblastoma which is known for producing androgens (male hormones) like testosterone and inhibiting the production of female hormones like estradiol.

Conclusion and Clinical Importance

• This study, though focused on a single case, provides evidence that behavioral changes, particularly aggressive behaviours, in mares can signal potential health issues that veterinary professionals should investigate.
• It also emphasizes the necessity of considering hormonal examinations when diagnosing such issues, to provide clearer indications of specific diseases or conditions, such as arrhenoblastoma, and facilitate effective treatment strategies.