Equine anterior uveal melanocytic tumours with pigmented corneal striae: A case series

Summary This case series describes three horses with anterior uveal melanocytic tumours associated with uveitis, glaucoma and pigmented corneal striae. The cases involved a 16‐year‐old blue roan Quarter Horse mare; a 10‐year‐old grey Thoroughbred gelding; and a 6‐year‐old grey Thoroughbred broodmare. Two were confirmed melanocytomas histologically and one was suspected. All horses exhibited multifocal‐pigmented corneal striae with concurrent uveitis and corneal oedema; two had visible iridial masses. Chronic secondary glaucoma was suspected in all cases, and no dermal melanocytic tumours were identified. Enucleation was performed in all cases, with histopathology confirming anterior uveal melanocytoma in two horses and unavailable for the third. Histopathology revealed melanin pigment and melanin‐laden cells lining breaks in Descemet's membrane. The presence of pigmented corneal striae in these cases was associated with glaucoma secondary to intraocular melanocytic disease and represents a novel clinical finding. The presence of pigmented corneal striae should therefore warrant investigation for intraocular melanocytic neoplasia as the underlying cause for glaucoma.