JVD 2020 #1 Presentation, Diagnostic Imaging, and Clinical Outcome of Conventional Ameloblastoma in Dogs; Tjepkema Flashcards
What are the cytologic features of ameloblastomas?
Differentiated ameloblasts (cells that produce enamel) and/or enamel organ differentiation but do not induce differentiation of odontogenic mesenchyme (ie no induction of the dental papilla or tooth-like structures)
Where is the ameloblastoma neoplastic epithelium assumed to arise from?
Previously quiescent remnants of odontogenic epithelium that remain within the periodontium.
For centrally located (within the jaw bone)- likely arise from rests of Malassez or other entraped/ectopic remnant of enamel organ.
For peripherally located (ie within gingiva) likely arise from rests of Serres
What are the 4 biologic subtypes of ameloblastoma in humans?
Peripheral- least aggressive, no bone involvement
Desmoplastic (1 case in dog)
Unicystic- (not reported in animals)
Solid/multicystic- variants: follicular, plexiform and acanthomatous
What was the mean/median age of dogs that had conventional ameloblastoma in the study?
8.9/9 years
How did conventional ameloblastoma present clinically- appearance?
A mass causing focal swelling and expansion within the jaw. The tumors often had a smooth surface of intact gingiva and/or mucosa with occasional fluctuant and dark-purple-blue cystic areas.
What was the most common area affected?
Maxilla (13/20) compared to 7/20 mandible. Most in the canine/premolar region
In those cases with diagnostic imaging available, what were the key features noted?
Loculated intraosseous lesion
Cystic features- central radiolucency with corticated border 11/13 cases.
More often a multicystic/multilocular pattern on rad and CT
Jaw bone lysis in 4/6 CT studies
Mixed lytic/proliferative pattern
External tooth resorption
Contrast enhancement in all cases with CT
Histopathology of canine conventional ameloblastoma
Neoplastic odontogenic epithelium without induction of odontogenic mesenchyme or formation of tooth structures.
Odontogenic epith. had recognizable ameloblast-like cell morphology: tall cuboidal to columnar layer of basal cells with palisaded nuclei in the apical cytoplasm
Histo patterns seen similar to humans: basal, plexiform and follicular
What was the treatment and outcome for cases in the study?
Most had wide surgical excision (17/20) and none had regrowth.
Half had narrow margins <0.5cm on histo