Equis ISSN 2398-2977

Teeth: tumors

Synonym(s): Odontoma

Contributor(s): Chris Whitton


  • Rare.
  • Cause: congenital and acquired.
  • Signs: mandibular tumors - firm swellings; maxillary tumors - rapidly growing, swelling, signs of upper respiratory tract disease; periodontal disease, halitosis, abnormal head carriage.
  • Diagnosis: radiography, histopathology.
  • Treatment: excision, radiotherapy.
  • Prognosis: generally poor, but variable depending on tumour type and location.



Tumor types
  • Ameloblastoma.
  • Hamartoma/osteoma.
  • Osteosarcoma.


  • Mandible - beneath any of the cheek teeth.
  • Maxilla - at base of cheek teeth, may extend into sinuses.

Sinonasal tumors

  • Equine sinonasal tumors are relatively uncommon in horses (non-neoplastic growths such as maxillary (sinus) cysts, progressive ethmoid hematoma and inflammatory nasal polyps are more common).The equine paranasal sinuses, especially the caudal maxillary sinus, are the most common sites for sinonasal tumors.
  • The more common tumor types include squamous cell carcinoma that, in some cases, arise in the oral cavity and spread to the maxillary sinuses; adenocarcinomas; bone and dental tumors; fibrosarcomas and hemangiosarcomas.


  • Maxillary tumors tend to be fast-growing.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Kock Eet al(2014)Magnetic resonance imaging of a solid, multilobular ameloblastoma in the mandible of a pony.Equine Vet Educ 46(11), 599-604VetMedResource.
  • Barakzai S Z (2008)Odontogenic tumours in the horse and man - difficulties with classification and the need for collaborative research.Equine Vet Educ20(12), 655-656VetMedResource.
  • Hackett E S & Baxter G M (2008)Odontogenic tumours in the horse.Equine Vet Educ20(12), 652-654VetMedResource.
  • Snyder C, Dubielzig R R, Gengler W & Livesey M A (2008)Surgical treatment of a rostral mandibular complex odontoma in a 3-year old horse.Equine Vet Educ20(12), 647-651VetMedResource.
  • Kutzler M A, Feleciano J & Valentine B A (2007)Madibular ameloblastoma in a mare.Equine Vet Educ19(9), 463-468Wiley.
  • Brounts S H, Hawkins J F, Lescun T B, Fessler J F, Stiles P & Blevins W E (2004)Surgical management of compound odontoma in two horses.JAVMA225(9), 1423-1427PubMed.
  • Dixon P Met al(2000)Equine dental disease Part 3 - a long-term study of 400 cases - disorders of wear, traumatic damage and idiopathic fractures, tumors and miscellaneous disorders of the cheek teeth.Equine Vet J32, 9-18PubMed.
  • Head K W, Dixon P M (1999)Equine nasal and paranasal sinus tumors. Part 1.: review of the literature and tumour classification.Equine Vet J157(3), 261-278PubMed.
  • DeBowes R M, Gaughan E M (1998)Congenital dental disease of horses.Vet Clin North Am Equine Pract14(2), 273-289PubMed.
  • Lane J G, Gibbs C, Meynink S E, Steele F C (1987)Radiographic examination of the facial, nasal and paranasal sinus regions of the horse - I. Indications and procedures in 235 cases.Equine Vet J19(5), 466-473PubMed.