Partial vertical ear canal resection in two cats.

Abstract

An 18-year-old domestic medium-hair cat (cat 1) and a 16-year-old domestic shorthair cat (cat 2) were evaluated because of obstructive skin lesions involving the perimeter of the left external auditory canal. Otitis externa was present in affected ears secondary to obstructive soft tissue growths involving the outer margin of the external auditory canal and outer third of the vertical ear canal. Histologic examination of a preoperative biopsy sample revealed multiple ulcerated ceruminous gland adenomas in the affected ear of cat 1. Histologic examination of the submitted tissue from cat 2 confirmed ceruminous cystomatosis with surface colonization of yeast compatible with Malassezia spp. Both cats underwent partial resection of the upper third of the affected vertical ear canal and associated diseased skin. The incised margin of the pinna was sutured to the margin of the remaining portion of the vertical ear canal with absorbable sutures. Both cats were disease free over a 12-month (cat 1) or 10-month (cat 2) follow-up period. Cat 1 later developed a small ceruminous gland adenocarcinoma in the adjacent rostrolateral margin of the vertical ear canal 1 year after surgery; the mass was resected, and the patient was free of recurrence 4 months later. Partial resection was an effective alternative to complete vertical ear canal resection for lesions involving the upper third of the vertical ear canal in these cats; the partial resection procedure was deemed simpler to perform and less traumatic to the cat. Functional and cosmetic results were excellent, with preservation of the overall anatomy of the external auditory canal.