Cysts are epithelial-lined cavities containing fluid or semisolid material. Odontogenic cysts derive from odontogenic epithelium in the jaws and may be developmental (e.g., dentigerous cysts) or acquired (e.g., radicular cysts) lesions. Odontogenic cysts are not common in dogs and are even less common in cats, but they may cause animals significant discomfort and pain. Odontogenic cysts may also enormously enlarge (they expand by accumulation of fluid within the cavity), which may lead to bone loss, jaw fracture and/or other complications. If these cysts are diagnosed and treated early, prognosis is excellent.
Most common (71%) are dentigerous cysts. These cysts are associated with unerupted teeth (can be found in 44.4% of unerupted teeth in dogs and in 20% of unerupted teeth in cats), most commonly with first premolar tooth on the lower jaw. Dentigerous cysts more commonly affect brachycephalic dogs and were associated with 90% of unerupted teeth in boxers. Most commonly these lesions are incidental findings on dental radiographs – this is one of the reasons why all areas of missing teeth should be radiographed.
Odontogenic parakeratinized (keratinized odontogenic) cysts represent 22% of odontogenic cysts. This type of cyst is commonly found affecting upper jaw and is associated with otherwise normal and vital tooth/teeth. The reason for their occurrence is not yet understood.
Other types of odontogenic cysts are described in dogs and cats, such as traumatic gingival inclusion cyst, radicular cyst (associated with non-vital teeth), lateral periodontal cyst and furcation cyst (mostly found in the furcation area of the maxillary fourth premolar tooth).
Most odontogenic cysts can be diagnosed with dental radiographs, but if the lesion is big and/or of an atypical appearance, advanced imaging (e.g., CT, CBCT) will be recommended.
Treatment of choice is surgical removal, where we have to extract the tooth/teeth involved with the cyst and remove all of the cyst lining (i.e., cyst enucleation). Epithelial remnants may serve as the nidus for recurrence, although the prognosis is generally excellent. Marsupialisation of (especially large) cysts is also possible, leading to reduction of the cyst size over a few months.
As malignant transformation of the cyst is possible and because some oral tumors may present as cyst-like lesions in the jaws, we will always recommend the tissues removed during surgery to be submitted for further examination.
To confirm complete healing of the cyst, radiographic re-check in 6 months is recommended.
If you have noted any problems with your animal, please consult your veterinarian.
Selected references:
- 1. Babbitt SG, Bell CM, Raleigh M, Haggerty K, Feigin K (2022). Cystic odontogenic tumor with features of calcifying odontogenic cyst in 3 cats and a dog. J Vet Dent 39(2):194-202.
- 2. Babbitt SG, Krakowski Volker M, Luskin IR (2016). Incidence of radiographic cystic lesions associated with unerupted teeth in dogs. J Vet Dent 33(4):226-233.
- 3. Bellei E, Ferro S, Zini E, Gracis M (2019). A clinical, radiographic and histological study of unerupted teeth in dogs and cats: 73 cases (2001-2018). Front Vet Sci 6:357.
- 4. Clayton DJ, Bell C, Feigin K, Shope B (2022). Clinical, radiographic and histologic evaluation of 40 cystic oral lesions in 37 cats. J Vet Dent 8987564221119956.
- 5. Haseler J, Tundo I, Southerden P (2023). Marsupialisation of 12 odontogenic cysts in Boxer dogs: Retrospective case series. Front Vet Sci10:1099128. doi: 10.3389/fvets.2023.1099128. eCollection 2023.
- 6. Holly VL, Zwicker LA, Starrak G, Leis ML, Bauer BS, Osinchuk S, Sandmeyer LS, Grahn BH (2018). Odontogenic parakeratinized cyst resulting in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a dog. Vet Ophthalmol 21(5):539-543.
- 7. Johnson J, Scott K, Bell CM (2022). Characterization and classification of keratinized odontogenic cysts in 29 dogs. J Vet Dent 39(2):182-193.
- 8. LaDouceur EE, Walker KS, Mohr FC, Murphy B (2014). Odontogenic keratocyst in a cat. J Comp Pathol 151(2-3):212-216.
- 9. Soukup JW, Bell CM (2020). The canine furcation cyst, a newly defined odontogenic cyst in dogs: 20 cases (2013-2017). J Am Vet Med Assoc 256(12):1359-1367.
- 10. Tjepkema J, Soukup JW, Bell C (2017). Suspected lateral periodontal cyst presenting concurrently with canine acanthomatous ameloblastoma in a 2-year-old standard poodle. J Vet Dent 34(3):141-147.
- 11. Verstraete FJM, Zin BP, Kass PH, Cox DP (2011). Clinical signs and histologic findings in dogs with odontogenic cysts: 41 cases (1995 – 2010). J Am Vet Med Assoc 239(11):1470-1476.
