Odontogenic hamartomas in cultured angelfish (Pterophyllum scalare)

Background: Odontogenic tumors present diverse clinical and histopathological behaviors that range from benign odontoma or hamartoma lesions to malignant tumors. In angelfish Pterophyllum scalare, findings of tumorous masses have been reported in the frontal region of the mouth, encompassing both the maxilla and mandible. Histologically, oral tumors have been characterized as angelfish lip fibroma or ameloblastoma. Methods: In this report, we describe the occurrence of a compound odontoma/hamartoma in 60 angelfish from a population of 300, all of which were collected from a Mexican ornamental fish farm. Results: All fish presented a tumor-like mass on the rostral part of the mouth. Histological analyses revealed the tumor-like mass was covered by a hyperplastic stratified squamous epithelium, with fully differentiated denticles in various states of organization, immersed among normal dental tissues and showing a mild disorganized pattern. Radiograph analysis revealed radiopaque denticles in a radiolucent protuberance. Bacterial and viral isolation procedures and electron microscopy analysis revealed no presence of these microorganisms. Conclusion and clinical relevance: Although findings of odontogenic tumors in the mouth of angelfish are reported as sporadic, our study detected odontogenic mouth tumors in 60 angelfish, but the possible cause of alteration is not yet clarified. Further research is needed to clarify pathogenesis and to identify possible genetic abnormalities.