Heterotopic hairs in the tongue of two dogs.

The occurrence of hairs in the median sulcus of the tongue in two dogs, a 7-year-old Rottweiler and a 10-year-old Cocker spaniel, is reported as an incidental observation at necropsy. The gross pathology of both cases and the histological and scanning electron microscopical findings in one case indicated a heterotopic development of the hairs, with secondary inflammation. The term pili heterotopici mediani linguae is suggested.