Life threatening hemorrhage associated with a dentigerous cyst in a dog: Case report.

Dentigerous cysts are the most common type of odontogenic cysts and arise from an unerupted tooth. These cysts have stereotypical radiographic and clinical findings. They can be extremely invasive but rarely present as a life-threatening emergency. This case report describes the stabilization and treatment of a 6-year-old mixed breed dog with a dentigerous cyst with concurrent life-threatening hemorrhage. The dog presented with severe oral hemorrhage from the mandibular artery and required multiple blood transfusions. It was ultimately diagnosed with a dentigerous cyst. Complications from dental issues and potential life-threatening complications, such as this case, can be prevented by routine annual oral examination and full mouth dental radiographs if an unerupted tooth is suspected.

Clinical, Radiographic and Histologic Evaluation of 40 Cystic Oral Lesions in 37 Cats.

Feline cystic oral lesions are uncommon and include odontogenic cysts and cystic odontogenic tumors. Accurate diagnosis requires close collaboration between the clinician's clinical and radiographic findings and the pathologist's histologic interpretations. The odontogenic cysts identified in this series include a periapical cyst, dentigerous cysts and a type of unclassified collateral cyst that appears to be a previously undefined, distinct entity in cats (UCC). Many of the cysts (52%) were unable to be classified due to insufficient diagnostic information, which often related to the associated tooth being unavailable for evaluation. Cystic odontogenic tumors included ameloblastomas, amyloid producing ameloblastomas (APA), and feline inductive odontogenic tumors (FIOT). The purpose of this case series was to assess correlations between clinical and radiographic findings, histopathologic interpretation and signalment to identify common characteristics and provide recommendations for clinicians and pathologists to optimize diagnostic efficiency and accuracy for cystic oral lesions in cats.

Correlation Between Radiographic and Histopathologic Findings Associated with Unerupted Teeth in Dogs.

An association between unerupted teeth and dentigerous cysts is well known,1- 4 however little is known about the presence of disease and histopathologic changes in unerupted teeth without radiographic evidence of cyst formation. Forty-two dogs representing 25 breeds, ranging in age from 5 months to 12 years were selected based on radiographic evidence of an unerupted tooth or teeth, either as a primary complaint or incidental finding. Dogs meeting the study criteria were presented to a private dental referral practice within a period of eighteen months from December 2016 through May 2018. Patients were treated with conservative en bloc resection of the unerupted tooth and overlying bone as well as debridement of any cystic structure and biopsy of the samples collected. Radiographs were evaluated using criteria previously established to assess for evidence of a cyst.1, 5- 7 A total of 68 unerupted teeth were identified; 63 (92.7%) were mandibular first premolar teeth. Of the 63 unerupted mandibular first premolar teeth, 28 (44.4%) had radiographic evidence of a cystic structure. Histopathology revealed that 21 of 28 (75.0%) had evidence of non-keratinizing stratified squamous epithelium consistent with a cyst lining. Of the remaining 35 of 63 (55.6%) mandibular first premolar teeth with no radiographic evidence of a cyst, 27 (77.1%) had no histologic evidence of epithelium associated with the impacted tooth. Notably however, the remaining 8 of 35 (22.9%) unerupted teeth without radiographic evidence of a cyst did have histologic evidence of non-keratinizing stratified squamous epithelium associated with the impacted tooth.

Heterotopic Polyodontia: Diagnosis and Surgical Removal of a Dentigerous Cyst Comprising 2 Dental Structures in a 14-Year-Old Horse.

A 14-year-old American Paint Horse mare was referred for further evaluation of a firm mass with an associated draining tract at the base of the left ear suspected to be a dentigerous cyst. Approximately three months prior, the draining tract had been excised under the presumed diagnosis of an abscess with no improvement. Physical examination revealed a firm mass palpable at the base of the left ear with a draining tract that did not elicit any pain response on palpation. Digital radiographs revealed a 6x11cm mineral mass in the left temporal region. Medially, there were two projections that extended into the left temporal bone. Cone beam computed tomography (CT) showed mild thinning of the temporal bone separating the mass and the brain at the conical extension of the caudal aspect of the mass. Both structures were isolated and elevated using a combination of osteotomes, mallet, and bone rongeurs under general inhalant anesthesia with radiographs to determine complete removal. Although histopathology was declined, gross examination of both structures resembled adult molar teeth. At eight months postoperative, the owners reported that the surgical site was healed and no discharge was present. Dentigerous cysts should remain a differential for a mass with an associated draining tract at the base of the ear in horses. Practitioners should strongly consider CT when feasible for additional diagnostics in similar cases. Although benign and removal poses risk, dentigerous cysts can be surgically excised with a positive outcome.

Incidence of Radiographic Cystic Lesions Associated With Unerupted Teeth in Dogs.

Medical records and radiographs were retrospectively reviewed over a 3-year period (2012-2015) from dogs presented to a private dental referral practice. Medical records were evaluated for the diagnosis of impacted or embedded teeth. The identified dogs' radiographs were reviewed for the presence of radiographically significant cystic lesions that were associated with the impacted or embedded teeth. Radiographic criteria were established by the authors for the purposes of identifying cystic lesions in dogs of different breeds and sizes, using established indices from human dental pathology as a basis. When histopathology results were available, they were reviewed and reported. In this study, 136 dogs ranging in age from 3 months to 17 years were diagnosed with 213 unerupted teeth during the study period. There were 62 (29.1%) of the 213 radiographically apparent cystic lesions identified based on the criteria proposed in this study. In this study, 146 (68.5%) of the 213 unerupted teeth were identified as mandibular first premolar teeth. Histopathology was obtained on 28 (45.1%) of the 62 diagnosed cystic lesions. Dentigerous cysts accounted for 20 (71.4%) of the 28 cystic lesions. Brachycephalic breeds were overrepresented in this study. Boxer, pug, Shih Tzu, and Boston terrier dogs were most likely to present with cystic lesions associated with unerupted teeth. Seventeen (85%) of the 20 cases with a histopathologic diagnosis of dentigerous cyst were found within these 4 brachycephalic breeds.

Endodontic therapy of a mandibular canine tooth with irreversible pulpitis secondary to dentigerous cyst.

Dentigerous cysts are uncommon, yet are being reported with increasing frequency in the veterinary literature. Dentigerous cysts are a type of benign odontogenic cyst associated with impacted teeth, most commonly the mandibular first premolar tooth. Significant bone destruction can occur secondary to the expansion of a dentigerous cyst. The expanding cyst can lead to pathology of neighboring teeth, which can include external root resorption or pulpitis. Intraoral dental radiographs are imperative to properly assess the presence and extent of a dentigerous cyst, as well as the status of the neighboring teeth. This case report describes treatment for dentigerous cyst including cyst lining curettage, mandibular bone regeneration, and endodontic therapy for a canine tooth with irreversible pulpitis.

Bilateral dentigerous cysts in a dog.

Dentigerous cysts are infrequently seen in veterinary medicine, but the consequences of an undiagnosed dentigerous cyst can be severe. Dentigerous cysts, that can be sub-classified as eruption or follicular, are a type of benign odontogenic cyst. They can cause significant bony and dental destruction associated with expansion if they remain undiagnosed for a period of time. Dentigerous cysts are secondary to embedded or impacted teeth, however not every impacted tooth subsequently forms a dentigerous cyst. Intraoral dental radiographs are necessary to differentiate a missing tooth from an impacted tooth. This case demonstrates the successful surgical management of a dog with bilateral impacted mandibular canine teeth, with secondary dentigerous cyst formation.

Immunohistochemical analysis of a dentigerous cyst in a dog.

A dentigerous cyst is a cyst that encloses part or the entire crown of an impacted or late-erupting tooth and occurs with comparatively high frequency in humans. In animals, there are three different lesions that are similar to dentigerous cyst and this complexity has led to confusion. In order to clarify the dentigerous cyst most similar to that in humans especially with regard to characteristics of the lining epithelium, this report describes the clinical, pathological, and immunohistochemical features of a dentigerous cyst in a dog. Further, approaches to the surgical and dental management of this cyst in dogs are also discussed and the literature is reviewed. Extraction of an embedded right mandibular first premolar tooth and debridement of the dentigerous cyst soft tissue lining were performed in a 4-year-old female mixed-breed dog. Radiography showed a well-defined unilocular and radiolucent area associated with the crown of the unerupted tooth. Histologically, the unilocular cyst wall was mainly lined by non-keratinized stratified flattened epithelium. As in humans, canine dentigerous cyst can be appropriately treated by cyst enucleation after accurate diagnosis. The radiographic appearance of an unerupted tooth embedded in an osseous cyst wall is a significant characteristic finding. Moreover non-keratinized epithelium is immunoreactive for amelogenin and ssDNA, which might be associated with deregulation of cell death in the lining epithelium, derived from odontogenic origin. When encountering any questionable lesions, an accurate diagnosis and immediate treatment can avoid malignant transformation.

Bilateral mandibular dentigerous cysts in a dog.

Cysts in the dental cavities of dogs are rare. This report documents the case of a young boxer that was referred after having had treatment for bilateral oral swellings. Dentigerous cysts were tentatively diagnosed. Surgery was performed to aspirate the fluid and remove the first premolars, which were positioned in the cysts. Histopathological examination of tissue collected during the surgical procedure confirmed the diagnosis.