Guinea Pig lump- open wound under chin

Question

Lump under chin   Hi, my guinea pig has quite a large lump under her chin. We found it a few months ago and the vet didn't know what it was but gave us some medical sealant to put on it to try to prevent the bleeding. Due I her old age (about 6 1/2 years) and the fact that it doesn't seem to bother her at all, we decided against surgery.

However it is still weeping and the sealant doesnt seem to be working in healing the wound; it is literally always sticky looking and covered in blood, so much so that whenever i pick her up i get blood on my hands.When I try to clean it with warm salt water she squeaks in pain and bits of the scabby lump and blood clots come away on the cotton wool. I don't think it is particularly hard but I can't squeeze it too much because she finds it so painful. It isn't seeming to heal at all. What do you think it could be? She definitely doesn't seem bothered by it and remains the dominant out of the two guinea pigs we have and she still enjoys running around on the grass outside. I don't think we will do anything because guinea pigs don't take anaesthetic well, especially at her age, but we just want to know what it is and how we can get it to heal? Thanks.
Photo included

Answer
Guinea pigs will sometimes get abcesses under the chin, called a subglottal cyst. Sometimes they open on their own, drain and then heal. This wound doesn't look like a subglottal cyst. It appears more to me like a malignancy of some sort.

The only way to find out would be a biopsy. Having said that however, you already acknowledge that she's an old girl and wouldn't do well with anesthesia. The other consideration is that if you did find it was cancerous would you have the resources to spend to try to treat it. At her age this would not likely be a wise thing to put her through anyway.

At six and a half years old she's already passed the expected life span of most pigs. Since this doesn't bother her I would recommend you just treat it topically as you're doing and leave it alone. Why put her through what would most likley be expensive treatment for something that would not be in her best interest.

Let her finish out her days as she is, happy and oblivious to this thing. She just may live even longer than you would expect without ever being bothered by this wound. Sometimes the best treatment is the least treatment and I think this is the case now.