Cartilaginous choristoma of the lip in a dog

Abstract

A six-year-old castrated male Maltese dog presented to a private animal clinic with a mass on the dog's lower lip without any other clinical signs. The mass (3 × 2 × 2 cm) was whitish and grossly well circumscribed, and a histopathological examination revealed that the mass was composed of normal cartilage tissue surrounded by fibrous connective tissues. Based on the gross findings, histopathology and anatomical location of the mass, the first diagnosis of a cartilaginous choristoma in a dog was made.

Fig. 1.

Histopathology of cartilaginous choristoma on the lower lip of a dog. (A) Lower magnification of cartilaginous choristoma in the submucosa. The expansile mass was sharply demarcated by surrounding connective tissue, accompanied by focal ulcer (arrows). (H&E staining, original magnification of insert = 12.5×) (B) Higher magnification of upper photomicrograph. The mass mainly consisted of premature or mature chondrocytes with lacunes and surrounding hyaline matrix. Note that cellular or nuclear atypia in chondrocyte was not observed. (H&E staining).