Keratoacanthoma of the spectacle in a Boa constrictor

ANIMAL STUDIED: A Royal Boa constrictor presented with retained spectacle of the right eye and a tumor-like appearance of the left eye.

PROCEDURE: The snake was euthanized, the head fixed in buffered formaldehyde, and histologic examination of both spectacles and both eyes performed.

RESULTS: The left orbital rim encircled a solid, scaly mass projecting 5-6 mm from the spectacular area. A cup-shaped tumor with a central keratin plug was observed microscopically. There was a thickening of the proliferating squamous epithelium, with squamous eddies and single cell keratinization. A few mitotic figures were seen in the basal layers but the tumor showed no infiltrative growth. The same morphology was observed in the right eye but to a lesser extent. The remaining parts of the eye were normal.

CONCLUSIONS: The diagnosis was keratoacanthoma and this is the first reported keratoacanthoma of the spectacle in a reptile. Keratoacanthoma should be considered as a differential diagnosis when trying to remove retained spectacles from a reptile eye.