Spontaneous repair of the atrophic contralateral ovary without ovariectomy in the case of a granulosa theca cell tumor (GTCT) affected mare.

The study documents the case of a 21-year-old thoroughbred mare who spontaneously recovered from an ovarian condition without any specific treatments. The mare had a granulosa theca cell tumor on one ovary and the other ovary was atrophic (shrunk), but regained normal activity over time.

Background of the study

• The focus was on a 21-year-old thoroughbred mare that had a granulosa theca cell tumor (GTCT) in her right ovary.
• The mare also had an atrophic contralateral (opposite side) ovary. Normally, in cases with GTCT, the contralateral ovary is often atrophic or becomes inactive.

Methods used

• Upon arriving at the research lab, the mare was clinically diagnosed with GTCT using rectal palpation and an ultrasound image of her ovaries.
• Throughout the breeding and non-breeding seasons, the mare’s blood was sampled from the peripheral blood for hormonal analysis.

Key findings

• Remarkably, 19 months after the initial examination and without any specific treatment for GTCT, the atrophic ovary was observed to have regained normal activity.
• The ovary was now home to follicles of different sizes, a sign of normal reproductive function. This indicated that the spontaneous recovery of the mare’s ovarian activity had occurred.
• Conversely, the right ovary, which initially had the GTCT, became smaller after 4 months and was completely inactive without any follicle. This result affirmed the debilitating effect of GTCT on equine ovaries.

Conclusion of the study

• In some cases of GTCT, a mare can return to a normal reproductive cycle without any treatment for the GTCT affected ovary.
• This study reveals a previously undocumented example of spontaneous recovery from ovarian atrophy in horses. However, further research will be needed to better understand why the recovery occurs and under what circumstances.