Moderate

Melanoma

Melanoma is a pigment-cell tumour — common in grey horses, often under the tail, on the lips, eyelids, or around the parotid. It is not sarcoid (a bovine papillomavirus tumour) and not ringworm (a fungal infection). A photograph cannot diagnose melanoma. Diagnosis is a vet exam and usually histopathology. The skin scan is a first look at the lump, not a verdict that your horse has melanoma, and there is no melanoma scanner.

Symptoms to watch for

A firm, dark, or flesh-coloured lump under the tail, on the lips, eyelids, or around the parotid

A lump that slowly enlarges, ulcerates, or bleeds after being knocked or rubbed

More than one lump, especially on a grey horse

A swelling in front of the ear or at the throat that can look like a swollen gland

Difficulty passing manure, eating, or blinking if a lump sits under the tail, in the mouth, or on an eyelid

Some melanomas stay small for a long time; a change in size or surface is a reason to book a vet, not a photo verdict

Common causes

A pigment-cell (melanocyte) tumour — common in greys, not the same condition as sarcoid (BPV) or ringworm (fungal)
A lump under the tail, on the lips, eyelids, or around the parotid — location is a clue, not a diagnosis
Individual susceptibility; some greys grow more than one melanoma over time
Trauma, picking, or rubbing that can turn a quiet lump into a larger, rawer growth
Not sarcoid and not ringworm — those can look similar and need a vet

Prevention

Watch lumps on greys, especially under the tail, lips, eyelids, and parotid, and book a vet rather than waiting for a photo guess
Check those sites when you groom so a new lump is noticed early
Do not pick, ligate, burn, or 'treat' a lump from a web article or a scan result
Do not treat a photo, a lump, or a scan result as a diagnosis
Skin photos can help you and your vet track a lump over time — they do not confirm or rule out melanoma

What to do

1
Book a vet visit for any new lump, especially on a grey. Diagnosis is a vet exam and usually histopathology, not a photograph.
2
Photograph the lump in good light and keep it on the horse's record so you and the vet can see change over time.
3
Do not cut, burn, freeze, ligate, or apply a cream from a photo guess — interference can make a lump worse.
4
Use a skin scan only as a first look at the lump to share, not as a melanoma test. There is no melanoma scanner.
5
If melanoma is confirmed, follow the plan your vet prescribes — that may include histopathology, monitoring, surgery, or referral. Do not start a treatment protocol from a photo.
6
Keep the vet on the same page. Share what you see; do not treat a photo as a verdict.

When to call the vet

Pick up the phone if…

Schedule a vet visit if you find a new lump on a grey — especially under the tail, on the lips, eyelids, or around the parotid — or a dark lump that is growing or changing. Call sooner if the lump is ulcerating, bleeding, interfering with the tack, the eye, or passing manure, or the horse is dull or off feed. A photograph cannot diagnose melanoma. Diagnosis is a vet exam and usually histopathology. Melanoma is a pigment-cell tumour — not sarcoid and not ringworm. The skin scan is a first look at the lump, not a verdict, and there is no melanoma scanner.