CYTOLOGICAL ASPECTS AND HISTOLOGICAL CORRELATION OF EPITHELIAL ODONTOGENIC TUMORSWITHOUT ODONTOGENIC MESENCHYME IN CANINE SPECIES

Background and Objective: Ameloblastoma and acanthomatous ameloblastoma represent tumor originating from odontogenic epithelium without odontogenic mesenchyme. The aim of the study was to describe the cytological features of ameloblastoma and acanthomatous ameloblastoma, and to compare them with histological findings. Materials and Methods: Evaluation of cytological characteristics of oral masses histologically classified as tumors of odontogenic origin was performed. Oral neoplasia involved maxilla (7) and mandible (2). Nine dogs were included in the study. There were 3 mixed-breed dogs, and one each of the following breeds: Fox Terrier, Labrador Retriever, Bobtail, Schnauzer, Schipperkee, Shih-Tzu. Age ranged from 7 months to 17 years. Results: Histological diagnoses included acanthomatous ameloblastoma (6) and ameloblastoma (3). Cytological diagnoses included ameloblastoma (4), acanthomatous ameloblastoma (3), and one low-grade epithelial neoplasia. One sample was hemodiluted. Cytological examination of ameloblastomas revealed tightly packed clusters of small basaloid-type cells, as well as larger interdigitating neoplastic cells showing mild pleomorphism and minimal anisocytosis and anisokaryosis. In cases of acanthomatous ameloblastoma, cytological examination often revealed variably sized clusters of oval to polygonal cells, and sometimes variable nuclear:cytoplasmic maturation asynchrony with characteristics of squamous differentiation. Histologically ameloblastoma was characterized by islands of proliferating odontogenic epithelium with low nuclear atypia. In acanthomatous ameloblastoma cords of odontogenic epithelium showed a more plexiform pattern. Keratinization was sometimes present. Discussion and conclusion: The most striking characteristics of the odontogenic neoplasms consisted of tightly packed clusters of epithelial cells, oval to polygonal in shape. Some cellular atypia and asynchronous maturation of the nucleus and cytoplasm were more commonly detected in acanthomatous ameloblastoma.