Sweetbriar

Grey Horse Melanoma

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Has anyone had experience with grey horse melanoma. I've been reading about this and from what I can find online about 85 percent of grey horses have at least one melanoma by age 15. Most never cause any problems and they can be removed surgically, but just wondering if anyone has an "old" grey horse and has experience with this? Thanks.

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From what I am reading its the black skin that is most susceptible. As the hair turns more white through aging the skin becomes more likely to develop the cancer. And apparently it has little to do with the sun - it's more related to the gene that causes the grey hair. Some greys will be fine and only develop a problem around and under their tails but others will have problems around the mouth and ears. Apparently it only effects internal organs very very rarely. But it becomes a visual problem oftentimes and can hinder defication, etc. Under the tail is the most common area for the melanoma and some people do not notice it until its been there for quite a while.

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From what I am reading its the black skin that is most susceptible. As the hair turns more white through aging the skin becomes more likely to develop the cancer. And apparently it has little to do with the sun - it's more related to the gene that causes the grey hair. Some greys will be fine and only develop a problem around and under their tails but others will have problems around the mouth and ears. Apparently it only effects internal organs very very rarely. But it becomes a visual problem oftentimes and can hinder defication, etc. Under the tail is the most common area for the melanoma and some people do not notice it until its been there for quite a while.

True

The melanoma has nothing to do with the color of the skin,, and grey horses started out with colored hair coat, with the greying gene working on the hair, so that it does not take up the melanin,and thus it accumulates in the skin, thus pre disposing the horse to a melanoma (skin cancer originating with that color pigment, and also why human melanonas often start in black moles

Reference:

'The etiology of melanomas in horses has not been clearly determined. One dominant theory is that melanomas in older grey horses are due to disturbed metabolism of melanin. This is thought to lead to the development of new melanoblasts, or possibly to increased activity of melanoblasts in the area resulting in a central area of too much pigment production in the dermis. It is controversial as to whether ultraviolet radiation (sun exposure) plays a role in equine melanoma

as it does in humans. Because most melanoma lesions occur in regions not exposed to the sun, it seems unlikely that the sun plays as significant a role as it does in human melanoma.6'

Qoute

'Melanoma in grey horses is an often benign neoplasm (cancer) of melanocytes (pigment cells) that is usually found in the skin, although it can be found in other organs. 3 It is one of the most prevalent neoplasias seen, and it is described to be nearly ubiquitous in 8 to 10 year old grey horses, whereas it is much less common in horses of other colors. 3 One study estimates that up to 80% of grey horses over 15 years old develop melanoma. 4 Melanomas in grey horses are most often non-invasive. 3 Unlike human malignant melanoma, grey horse melanomas are encapsulated, and metastatic progression is prevented or slowed down by factors that are not yet known. 4'

Unfortrunately , Nick, both you and I need to worry, as Charlie is also grey, but at least not all her skin is darkly pigmented, as she was born with some white Appaloosa coat pattern

When grey horses are born, they have dark hair coats and skin. 4 As they grow older, their hair turns white while their skin remains dark grey in most cases. In some grey horses, their skin also becomes lighter as they age. People theorize that the high prevalence of melanoma in grey horses is due to the changes that occur in the skin and hair coat pigmentation with aging. 4 Some theorize that equine melanoma may represent a storage disease rather than a true cancer.3

However, another study specifically stated their findings that grey and non-grey horse melanomas are actual neoplasms and they resemble human malignant melanomas in terms of histological traits and immunostaining.4

Edited by Smilie

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I took in a "free" grey older Arabian gelding , sight unseen until unloaded here. First he was so thin he staggered when he got out of the trailer. Then I saw all his bumps. The one most notable was between his eye and ear (like his eyebrow). It was about the size of a golf ball. It didn't seem to hurt him. He had a few under his tail too and smaller bumps here and there. He was a sweet horse and lived a few years fat and loved here. We found him one morning dead. No signs of struggle , like he had a massive heart attack and just fell over. The vet figures he was full of cancer.

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As I have a grey also, and she is an Arabian, who seem to be rather at risk for the cancers.

You can see "Siseley" at about 3 yrs of age when she was first started to be actually ridden;

saddlebackandsis011.jpg

and here at 12 yrs old!!;

GEDC0409.jpg

you can see that we have gone from a nice Silver Dapple, to a bright White with flea bitten Chestnut now coming in. I believe that Greys are Chestnuts when born, and grey out when about 8mo to a year.

"Siseley's" full sister is a beautiful gleaming Chestnut!!

Named "PC Mystic Charmer" on the AHA records.

( Yeah, she got in a tussle with a feed bucket, and scratched her nose!)

Edited by siseley

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Greys can be any color when born. I saw a beautiful red bay colt (Arabian) with for matching stockings and a blaze turn grey by the time he was 6 months old and of course the Lippizan (Sp?) are born usually black. I love chestnuts with lots of chrome. I told my mare while pregnant this is what I wanted. That is exactly what I got...except I forgot to tell her I wanted the filly to stay that color. She is now white but when wet her chrome still shows.

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I've always wondered if it seemed to hit certain breeds more aggressively...I've known 3 QH (2 mares, one gelding) who all died fairly young (8-15yo) from melanomas ...all 3 were grey, of course.

Whereas the Arabs I've known who have gotten melanomas have all fine into their late twenties.

I had an 8yo half Arab x Qh/Morgan gelding who had what I thought was a melanoma. It was way back between his butt cheeks...the vet was impressed I even found it (I'm a very thorough groom! Lol) but it ended up just being an encapsulated fat pocket. That's the only run-in I've had so far with all the greys I've owned.

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I took my Torro (5yr old steel grey Arab) to the vet on monday to have a bump on his eye removed.. My vet had said that most grey Arabs die WITH melanomas not BECAUSE OF melanomas. I wonder if that applied to other breeds too? I don't have much experience with melanomas so well see I guess. So far, Torro is melanoma free.

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petebeforeandaft_zps02d17459.jpg

This is Pete. Top of picture is Pete just hours after he was unloaded. I was told he was a great trail horse. Never spooked. Well , yeah , he was nearly dead. The bottom is about 4 months later. He had several melanomas on him. He died of a heart attack just 3 years later.

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Grr dropped my mouse, and lost everything I had typed.

I love greys, and own one myself. My vet is great, and will shoo off people as needed, but if you care and are trying to educate yourself, then you are welcomed.

I have had horses all my life, but honestly just experienced colic for the first time last year, and then not my horse. I've been super lucky, so I have not seen anything really first hand, despite 30+ years ownership. I board and so the things that happened, happened when I was not there.

So vet was out, he did shots, sheaths, etc. Barn manager had a horse sedated for teeth pulling, and lifted the tail, there were lumps all over the area. I was horrified. Growths about all over that area. Horse is late 20s or early 30s, It freaked me out.

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^^this is why (as serah rose pointed out) it is important to groom or at least inspect thoroughly on a regular basis. i'm sure those lumps didn't sprout overnight.

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I guess what is somewhat comforting, concerning greys and melanomas, is that maligant melanoma, which is deadly in people, does not seem as invasive in horses, and probbaly, why, just like most men die with prostate cancer, versus due to it, so do many horses live with melanoma, rather than die from it

IIt can interfer with defication, and can at times, become very aggressive, as in people, thus spreading to deep main organs

Grey is nor a color, but rather an autosomal dominant color modifying gene. Thus, grey horses can be born any color, as stated, and if they inherit the greying gene from just one parent, it, like hypp witll be expressed.

The greying gene replaces pigmented hair with non pigmented hair, thus that melanin in the skin is not used, but rather builds up, and that is the mode in greying horses that leads to melanoma.

No breed is more suscepatble, but if that breed has a high population of greys, then of course, melanoma with be more common in that breed

I think that is why melanoma is thought to be more common in colored people, due to the high concentration of melanin in the skin, and malignant melanoma in Caucasions often occurs in a dark mole that goes malignant, usually from sun exposure

A link on the genetics of the grey gene

http://scienceblogs.com/grrlscientist/2008/08/06/premature-hair-graying-in-hors/

If you have abreed, like theArabian, then the incidence of melanoma in that breed is higer, just because there are more grey horses.

http://www.bendequine.com/documents/MelanomaArticle.pdf

Here is astudy done on Lipizzaners

Equine melanoma in a population of 296 grey Lipizzaner horses.
Source

Department of Clinical Surgery and Ophthalmology, University of Veterinary Medicine, Vienna, Austria.

Abstract
REASONS FOR PERFORMING STUDY:

Equine melanomas occur most commonly in grey horses at age 5 years or more. Generally, benign and malignant melanomas are distinguished by microscopy, but a more distinct classification would be helpful.

OBJECTIVES:

The objectives of this study were to gain further evidence concerning the occurrence of melanotic tumours, and to evaluate the impact of heredity on melanoma development.

METHODS:

A clinical study was conducted on a defined population of 296 grey horses of Lipizzaner breed. Individuals were classified according to their stage of disease using a 0-5 scale. Heritability was estimated on a sample of 296 grey horses with pedigrees traced back as far as 32 generations.

RESULTS:

Of the 296 horses, dermal melanomas were present in 148 horses (50%), 68 of which were more than age 15 years; 51 of these were melanoma-bearing. In 75.6% of cases, melanotic tumours were detected underneath the tail. Although melanoma-bearing grey horses were encountered up to stage 4, none of the affected individuals suffered any severe clinical effect or was handicapped in performance. Statistical analysis revealed highly significant effects of stud and age (P < 0.0001), explaining 28% of the total variability.

CONCLUSIONS:

In contrast to melanomas in solid-coloured horses characterised by early metastases, melanomas in grey horses showed less malignancy. Affected individuals often had encapsulated nodules or structures similar to human blue nevi. Grey horse-specific genetic factors inhibiting metastatic processes may be responsible for this phenomenon.

POTENTIAL CLINICAL RELEVANCE:

Although the obtained heritability estimate of 0.36 with a standard error of 0.11 indicates a strong genetic impact on the development of melanoma in ageing grey horses, a possible influence of the genes with large effects was also suggested. Therefore, further analysis is required of melanoma development in the ageing grey horse.

PMID: 12638791 [PubMed - indexed for MEDLINE]

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After reading all of this I promptly went outside, pulled my grey mare out of the pasture, and invaded her privacy quite thoroughly. She is now highly offended and I am satisfied there are no lumps or bumps. Told her we have an appointment for next week around the same time lol.

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LOL Sayge, that is great.

I remember reading about grey horse melanoma way back when I was a very young teenager - back then the only horses I owned were plastic. I subscribed to Horse Illustrated and hoarded and read those babies like they were my Bible. Grey's are my favorite - so I stashed the info in my head, knowing some day I'd have my dream horse ( A Grey Irish Draught gelding...named Jump the Moon. LOL. ooooooh those were the days...)

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^^this is why (as serah rose pointed out) it is important to groom or at least inspect thoroughly on a regular basis. i'm sure those lumps didn't sprout overnight.

Nick it was not my horse, but another boarders. I inspect my horse every time I am there, thoroughly. My vet welcomes tag alongs if you are not a pain in the rear, and so I stuck with him while he treated the other horses at my barn, as he tells you what he is doing and why as he does it, and I like to learn. I couldn't believe it when he lifted the horses tail, it was hard to look at. Thankfully it's not blocking bathroom abilities, but I'd think before too much longer if more grow then it would have to.

The horses owner is absent, but she pays her board. For sure she knows, as the BM would tell her, but I have only seen her there once and I have been there over a year.

Get to know me a bit better :) I am super over the top about my horses care, no way in heck this would happen to my horse without me knowing it. Sorry for not being clear in my post - I think I was irriated that I dropped my mouse and lost the whole thing I had typed out.

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^^? nowhere in my post does it say i considered you or anybody else were being negligent. i just suggested the importance of thorough and regular grooming or inspection on the part of us all.

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This is just a very interesting topic, and actually made me take Smilie to the vet this morning.

No, Smilie is not grey, Charlie is. Since I have not shown Smilie in two years, I am going to admit that I have not thoroughly washed her tail in two years!( to use internet slang-'my bad' ! )

A few days before this topic came up< i decided to give her tail a good wash and conditioning. I found a small dark nodual on the underneath side of her tail bone

Then, reading up on equine melanoma, and the last link i posted, seems grey horses have some built in protection mechanism that prevents many of the melanomas from becoming malignant

Well, Smilie is not grey, so I worried about a melanoma that would be aggressive like a human melanoma, thus took her to my vet for peace of mind

He assured me it was probably just a sebaceous cyst, that could just be ignored

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My 8yo grey mare has a gumball sized one on her rump. Need to take her in and get it removed and biopsied. It doesn't affect her in any way though so we haven't been in a hurry.

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The mare in my pic has melanoma. She has it pretty advanced, it's in her mouth and under her tail. I had the vet out and she said Smokee will pass on of old age before this will affect her, although she apparently has had it for a very long time.

Also, to mention, Smokee just turned 28 three days ago and is a foundation quarter horse. My vet also gave me around that same percentage of the grey horses that end up with it.

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Thanks for the information -- just bought myself a really nice gray mare. Will keep an eye on her rump area -- thanks again for the information.

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Bottom line-grey horses are prone to melanoma, because that skin pigment builds up in the skin instead of being used in that hair shaft.

Melanoma in horses often remains localized, thus is a blemish at most, However, It can become very malignant, and like any other cancer, spread to vital organs, and then it becomes deadly

I own a grey horse an dhope she won't come down with melanoma. Would I go out and purposely buy a grey horse-no!

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My TW started off as a dark chestnut sabino.

When I went to have her papers switched over to my name, I sent pictures and requested that her color was corrected.

Luckily, she came from a nearby ranch and the original owner/breeder sent in a letter stating that is was the same horse.

The nut that I bought her from had fled the state and moved back east.

Precy had two long narrow tumors on her inner thighs,that you couldn't see. But when I washed her legs I could feel them.

My vet thought they might have been caused by multiple hits (over time) by a whip as the nut was very fond of them as a "training aide".

I don't know if it was trauma or just being a grey horse. They never grew in size or shape and I showed the lady who bought her where they were.

I wouldn't own another grey horse because the soil around here is deep red and it tints a white coat to light pink.

People actually asked if I'd dyed Precy. :rolleye0014:

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You mentioned Melanoma but there is also another type of cancer grey horses get, Squamous Cell Carcinoma.

Squamous cell carcinoma generally shows up first in the skin, particularly around the eyes, on the ****** or vulva, and in other areas where skin meets mucous membranes. It's especially common in horses with pink skin in these areas, such as Appaloosas, Paints and some draft breeds.

Idaho is a grey horse and we found out last summer that she has this kind of cancer in the vulva area. Because of her advanced age, she will be 29 in March, the vets said the treatment would be worse than letting her live out her life. We thought we were only going to have a few months but she is still with us. Everyday she is here is a blessing.

Idaho is the first horse that had an stolen horse alert sent out to thousands on the internet in 1997, one we called the Idaho Alert. (Pre-dates the Amber Alert for people) We used the alert to help find her after she was stolen from our family. It took us 51 weeks to bring her home. We did catch our thief too.

Because of that alert, which is now called the NetPosse Alert, Stolen Horse International was founded as a nonprofit organization. Since then many horses have been found and thefts have been thwarted.

So you see, she is one special horse. She is the face of our organization and she is part of our souls. I look at her every day and know from experience that miracles do come true. She is walking proof.

Back to the cancer...didn't mean to get so sidetracked. I just wanted you to know there is more than Melanoma to worry about in grey horses. And yes, she does have pink skin, not black.

Debi

PS: If you want to read her story, my 1998 letter to the people who helped us in here: http://netposse.com/newsviewer.asp?id=13&P=1&cat=

49999webringthemhome2.jpg

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You mentioned Melanoma but there is also another type of cancer grey horses get, Squamous Cell Carcinoma.

Squamous cell carcinoma generally shows up first in the skin, particularly around the eyes, on the ****** or vulva, and in other areas where skin meets mucous membranes. It's especially common in horses with pink skin in these areas, such as Appaloosas, Paints and some draft breeds.

Idaho is a grey horse and we found out last summer that she has this kind of cancer in the vulva area. Because of her advanced age, she will be 29 in March, the vets said the treatment would be worse than letting her live out her life. We thought we were only going to have a few months but she is still with us. Everyday she is here is a blessing.

Idaho is the first horse that had an stolen horse alert sent out to thousands on the internet in 1997, one we called the Idaho Alert. (Pre-dates the Amber Alert for people) We used the alert to help find her after she was stolen from our family. It took us 51 weeks to bring her home. We did catch our thief too.

Because of that alert, which is now called the NetPosse Alert, Stolen Horse International was founded as a nonprofit organization. Since then many horses have been found and thefts have been thwarted.

So you see, she is one special horse. She is the face of our organization and she is part of our souls. I look at her every day and know from experience that miracles do come true. She is walking proof.

Back to the cancer...didn't mean to get so sidetracked. I just wanted you to know there is more than Melanoma to worry about in grey horses. And yes, she does have pink skin, not black.

Debi

PS: If you want to read her story, my 1998 letter to the people who helped us in here: http://netposse.com/newsviewer.asp?id=13&P=1&cat=

49999webringthemhome2.jpg

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true, a grey horse can also get other types of cancer, like any other horse, but Squamous cell carcinoma is not linked specifically to grey horses, but is common in any horse that has non pigmented skin in those areas mentioned

Melanoma , has a completely different etiology that is unique to grey horses, and arises not because of un pigmented skin, but rather that too much pigment builds up in the skin, as they greying gene prevents that pigment from being taken up by the hair shaft. Skin pigmentation is caused by the melanocytes, thus melanoma arises from excess pigment staying in the skin, rather than the absence of pigmentation, as in squamous cell carcinoma

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