What is this lesion, slowly growing over the past six months in this 18 year old horse? How should it be removed?
You don’t need to be an expert equine clinician or an ace oncologic pathologist to know that a black mass anywhere on a grey horse is a melanoma! But here complete resection might be difficult. The bleached section here shows few mitotic figures: this is a relatively benign melanocytoma, but with poor surgical margins obtained after resection from the canthus. Had it been in the third eyelid complete removal would have been easy but at the canthus we performed cryotherapy on the tissue following resection to prevent recurrence.