Anyone have experience with Granulosa Cell Tumor?

[ClickMini]

My little mini mare who just turned 3 years and is a hormonal psycho nut job just tested high for both estrogen and inhibins which is an indicator of granulosa cell tumor. She also has a very cresty neck, to an unusual degree for her age and body type. I think it is extremely rare for it to happen in such a young mare. She just turned 3 a few weeks ago.

Anyone here have experience with this? Wondering what to expect. I believe the recommendation is going to be removal of the ovary. I wonder if we leave the other ovary in if it's more likely she will have problems with that later?

Maybe I should just have a complete spay done on her. What a bummer. Poor little thing!

 

[Nathan Luszcz]

Yes, remove the ovary immediately. The other ovary will function normally after the body has time to sort out the hormones.There is no reason to ever spay a mare unless its a very serious uterine issue, but ovarectomies are relatively common. But there is no reason for that either, unless you just have no intention of breeding her and want a "gelding" of a mare. Be aware though she will still possibly tease, because the absence of progesterone more than the presence of estrogen is what allows the mare to show some signs of mild heat.

 

[drmatthewtaylor]

Removing the ovary is curative as GCT's are benign, its the hormones they secrete that cause the problematic behaviors. Mares will function almost normally on one ovary(fertility rates drop just a few percentage points). It usually takes a few months for the mare to return to normal post surgery.

If breeding was never a consideration and the behavior is not detrimental then the ovary could be left with no ill effects.

Dr Taylor

 

[Nathan Luszcz]

Uhm... respectfully, I disagree very strenuously. I've seen mares die from granulosa cell tumors that were the size of basketballs, or larger. Yes, the tumor itself is benign, but its physical presence alone can cause major issues, sometimes fatal. Not all tumors grow that large, but left untreated and unmonitored, you risk serious consequences. If its nice and small right now, take it out and avoid the trouble later. Besides, removing it as a small golf ball is much, much easier on the mare and the surgeon than removing it as a softball (for a mini). I have no idea how long the ones I saw took to grow, but by the time they were diagnosed and put on the table, it was too late. NORMALLY, they are discovered MUCH MUCH MUCH earlier, due to behavioral issues, so please don't think I'm trying to scare you! It may take years to get there. I'm just saying, address it soon, and don't just ignore it and think it's passive. It is not maligment, but even benign tumors can cause issues.

 

[ClickMini]

Thanks to both of you. Her behavior is actually quite horrible which is what made me run the panel to begin with. I call her the squeaky toy because the other horses touch her and she squeals like a little piggy. She also strikes and kicks quite strenuously. She has twice come at me like she was possessed which caused me to dislike her quite a lot. Yet, her base temperament is very quiet and sweet. So, even though the levels of inhibins and estrogen are borderline at this point, I think I'll be pretty proactive in diagnosing and dealing with it.

 

[disneyhorse]

I also agree removing the ovary would be a good idea.

Six year old andalusian mare my friend has had hers removed last month that was half the size of a basketball already... She had always been mellow but recently was acting like a stallion.

She's back to her old self again, easy surgery through her flank....