Ocular dermoid

From Felipedia

A 10-week-old Birman kitten with dermoid (choristoma) at the lateral canthus^[1]

Small ocular dermoid on medial lower canthus of 16-week-old Burmese kitten. Courtesy of Dr Jim Euclid

An ocular dermoid is a choristoma (normal tissue in an abnormal location) and represents one of many congenital eye diseases. Dermoids may be present on the eyelid but most frequently they are located on the lateral conjunctiva or cornea. The ocular dermoid is a variant to the more common dermoid sinus associated with the spine.

Reported in a group of inbred Birman cats, epibular dermoids are skin-like growths that are hairy, pigmented and attached to the conjunctiva at the corner of the eye. In all reported cases, only one eye was affected. The hairs of the dermoid caused irritation and inflammation, but removal of the growth resolved the problem. The mode of inheritance is not known, but a genetic factor is indicated due to the relatedness of the affected cats^[2].

Most eyelid dermoids are harmless. Commonly they can cause a mild conjunctivitis and hence require surgical excision, which is usually curative^[3]. Given the anatomy of the upper eyelid, its greater mobility and the effects of gravity, it is inevitable that surgery of the upper eyelid is more challenging than the lower eyelid. Succesful eyelid surgery aims to retain or construct eyelid margins to provide conjunctival lining and to preserve functional eyelid movement.

References

1. ↑ Barnett, KC & Crispin, SM (2002) Feline Ophthalmology: An atlas & Text. p: 35 Elsevier Ltd
2. ↑ Hendy Ibbs, PN (1985) Familial feline epibulbar dermoids. Veterinary Record 116:13-14
3. ↑ Peiffer, RL, Nasisse, MP, Cook, CS & Harling, DE (1987) Surgery of the canine and feline orbit, adnexa and globe. Part 2: Congenital abnormalities of the eyelid and cilial abnormalities. Companion Animal Practice August:27-37