Melanoma - skin tumour
There are numerous different causes of skin lumps in horses. One of the most common nodular skin diseases is melanoma, found predominantly in grey horses. It is uncommon in non-grey horses. Although often considered a benign tumour in horses, melanoma has malignant potential and can be locally invasive; early intervention to remove/treat any tumour is advised. Treatment is much more difficult in advanced cases. It is important to call your vet to examine any new or growing lumps you notice on your horse, particularly grey horses.