EQUINE UNILATERAL HETEROTOPIC POLYODONTIA: A CASE REPORT

Resumo

Heterotopic polyodontia have been described in most domestic species and human. Known as a dentigerous cyst but appropriately called heterotopic polyiodontics, it rarely occurs in horses, however it is easily recognized as a congenital defect. The cysts usually associated with this condition contain part or all of dental structures. The heterotopic tooth or dental structure is usually adhered to the temporal bone and surrounded by a secretory membrane, with a accumulation of exudate and draining tract along the proximal pinna or directly over the cyst. This case report describes in a 2.5-year-old female quarter horse, weighing 430 kg, with a heterotopic polyodontia that contained two easily small’s identifiable dental structures, presented for evaluation of a chronic intermittent mucopurulent exudate discharge from the right sub-auricular region in the mastoid process of the temporal bone and a drainage tract near the right pinna. The diagnosis is established with clinical, radiographic, ultrasound and confirmed by histopathological examination of the structures removed. The cystic capsule was surgically removed, measuring approximately 3.0 x 2.3 cm in diameter, filled with mucopurulent exudate and containing two dental structures within 0.5 cm in diameter and 0.2 cm in diameter. Microscopic examination revealed a cystic area covered by stratified squamous epithelium with a lympho-histio-plasmatic cell infiltrate in the dermis, which was compatible with heterotopic polyodontia. Postoperatively, there were no neuromotor sequelae and wound healing evolved positively.