We have a mare who is about 60 days pregnant. She had what we thought was a "boil" and the vet opened it up going on three weeks ago. She is on Uniprim to keep it from becoming infected. She is also on Regumate. There wasn't pus in the "boil" but chunks of whitish granular stuff came out. Since then she has had oozing of blood daily and the opening has stayed open. Now I am finding more lumps. These lumps are located on her lower legs, point of buttock, flank, and neck. They have come up since this "boil" was opened. I have read about disturbing melanoma and having it progress. At this time, we are just treating the open wound. She is not lame and is eating normally. We don't know what to expect other than just treating her normally. Has anyone had this experience? I tend to be a worry wart and speculate that the pregnancy may have triggered her melanoma's and they are spreading now. Our vet said that melanoma is not cancerous or metastatic, but it sure seems like she is getting lumps in other places. Thank you.
Melanoma is a malignant tumor of melanocytes which are found predominantly in skin but also in the bowel and the eye (uveal melanoma). It is one of the less common types of skin cancer but causes the majority of skin cancer related deaths. Malignant melanoma is a serious type of skin cancer. It is due to uncontrolled growth of pigment cells, called melanocytes. Despite many years of intensive laboratory and clinical research, the sole effective cure is surgical resection of the primary tumor before it achieves a Breslow thickness greater than 1 mm. It is more frequent in males and Caucasians, especially those living in predominantly sunny locales.
Malignant melanoma accounts for 75 percent of all deaths associated with skin cancer. Treatment includes surgical removal, adjuvant treatment, chemo and immunotherapy, or radiation therapy.
I highly doubt melanoma behaviour is different between species. Melanoma can and does become highly aggressive METASTATIC melanoma. In horses, grey horses have a statistically higher incidence of melanoma than other colours of horses.
It would probably be worth getting a second opinion from another vet other than your own (if you are not satisfied with his/her diagnosis), but it doesn't sound like a classic melanoma situation. It sounds more like a skin infection of some sort.
Carol: Melanoma is very different in the equine from the human, and horses rarely die of melanoma. Interestingly, one of the aspects of research conducted into the cloning of equines at the Idaho/Utah State Universities that resulted in the first clones (the mules) was investigation into the differences between equine and human cells, as humans die of both melanoma and prostate cancers, but equines (as noted) rarely die of melanoma, and don't get prostate cancer.
I've watched 3 different friends have horses die from aggressive melanoma that turned malignant. If a horse has malignant melanoma, it can be fatal. If the horse has benign melanoma, it is just unsightly and may only bother the horse if they're present under the saddle and girth. To say melanoma NEVER turns malignant in a horse is serious misrepresentation and it is this point in particular I took exception to. When melanoma becomes malignant it becomes metastatic, i.e. spreads, very quickly. The only difference in malignant melanomas between humans and horses is that for some reason men die from malignant melanoma much more frequently than human women do, whereas the incidence amongst the genders in horses is even. I am unclear as to why you'd mention prostate cancer in the same paragraph as melanoma? Prostate cancer is specifically a human disease requiring disease-specific detection, and it's disease behaviour and treatment are not even in the same league as malignant melanoma. I work in medicine, so I know quite a bit about it.
Please review the various posts - particularly mine - again.
You wrote: "I am unclear as to why you'd mention prostate cancer in the same paragraph as melanoma?
I had previously written: "Interestingly, one of the aspects of research conducted into the cloning of equines at the Idaho/Utah State Universities that resulted in the first clones (the mules) was investigation into the differences between equine and human cells, as humans die of both melanoma and prostate cancers, but equines (as noted) rarely die of melanoma, and don't get prostate cancer."
In other words my reference was to the cellular-level research associated with cloning that specifically looked at why horses don't have a high mortality rate from either melanoma or prostate cancer, but humans do. As you say "Prostate cancer is specifically a human disease - so the questions is why? And the difference between the equine and human cell may hold a reason - it was found (for example) that intracellular calcium levels are significantly different. I was commenting on research that looked at both cancers, not responding solely on the melanoma topic, but on a subject that encompassed a wider field.
I think that your observation "The only difference in malignant melanomas between humans and horses is that for some reason men die from malignant melanoma much more frequently than human women do, whereas the incidence amongst the genders in horses is even" is potentially misleading for some, although technically accurate. Melanoma in the equine - as I previously noted - is rarely fatal; while in the human the fatality rate is significant. The difference in metastasis is the factor to consider - rare in the equine, common in the human. It is important to clarify your observation as referencing malignant melanoma - that malignancy being rare in equines, not (equine) melanoma as a whole.
As an update - this "boil" thing closed up for several weeks. Just this morning it started oozing bloody discharge again. Not as large as before, but her hock area is swollen. She is not lame in any way and although probably somewhat tender, lets us touch it. I originally saw some "spreading" of these lumps and those lumps are still there, but no "new" lumps have arisen. I thought we were on the mend until this morning. The vet will be out tomorrow - but I may need a second opinion. My concern was the baby - as the mare doesn't seem to be affected by these lumps.
Just had her rechecked on day 76 - still pregnant!!! Baby was active and looked normal. Vet said he measured a 70 day baby - but that he had trouble measuring because baby was so active.
Please note that opinions, product information, advice or suggestions posted on this bulletin board are not necessarily those of the management at Equine-Reproduction.com nor does the maintenance of the post position indicate an implicit or any endorsement of that information, opinion or product.
Further, although we have the greatest respect for the posters offering assistance here, you are advised to seek a consultation with your veterinarian prior to using information obtained from this board if it is of a veterinary nature.Proud to be sponsored and supported by: