Maxillary Ameloblastoma in an Asiatic Black Bear (Ursus thibetanus)

An approximately 30-year-old intact female Asiatic black bear (Ursus thibetanus) was presented for annual examination and a history of ptyalism. A large 9.5 cm × 5 cm × 5 cm, firm, round mass was identified attached to the hard palate on physical examination. A computed tomography scan was performed, and the heterogeneous, mineral-attenuating mass was seen arising from the right aspect of the palatine bone and extending rostrally to the level of the last maxillary molars, caudally into the oropharynx, and dorsally into the nasal choana. Surgical debulking was performed to remove the portion of the mass within the oral cavity. Histopathologic analysis was consistent with a keratinizing ameloblastoma. Nine months postoperatively, the patient was asymptomatic for the tumor. The patient was euthanized 23-months postoperatively, and severe diffuse pustular dermatitis, growth of the ameloblastoma on the hard palate, and various degenerative and aging changes were noted on necropsy at that time. This is the first report of an ameloblastoma in a member of the Ursidae family.

Maxillary neoplasms in four dromedary camels

Four camels (Camelus dromedarius) presented to the Veterinary Teaching Hospital at King Faisal University with maxillary masses. On radiographs, the masses were multicystic and expanded the maxillary bone. The tumors were diagnosed by histopathologic examination as conventional ameloblastoma, two cases as intraosseous squamous cell carcinoma, and central odontogenic fibroma with ossification. To the authors' knowledge, this is the first report of ameloblastoma in a camel, the first detailed description of maxillary squamous cell carcinoma in camels, and the first report of central odontogenic fibroma in any animal species.

Research-Relevant Background Lesions and Conditions in Common Avian and Aquatic Species

Non-mammalian vertebrates including birds, fish, and amphibians have a long history of contributing to ground-breaking scientific discoveries. Because these species offer several experimental advantages over higher vertebrates and share extensive anatomic and genetic homology with their mammalian counterparts, they remain popular animal models in a variety of fields such as developmental biology, physiology, toxicology, drug discovery, immunology, toxicology, and infectious disease. As with all animal models, familiarity with the anatomy, physiology, and spontaneous diseases of these species is necessary for ensuring animal welfare, as well as accurate interpretation and reporting of study findings. Working with avian and aquatic species can be especially challenging in this respect due to their rich diversity and array of unique adaptations. Here, we provide an overview of the research-relevant anatomic features, non-infectious conditions, and infectious diseases that impact research colonies of birds and aquatic animals, including fish and Xenopus species.

Oral neoplasms in pickhandle barracuda Sphyraena jello from India

We report the spontaneous occurrence of oral neoplasms in pickhandle barracuda Sphyraena jello Cuvier, 1829 from Parangipettai, on the southeast coast of India. A total of 11736 fish were examined, of which 43 were affected with oral tumours, with an overall prevalence of 0.37%. Gross and clinical symptoms included reddish to grayish-white distended tumourous growths on the gingiva, intra-oral bones and tongue. The tumours exhibited delayed eruption and intra- or extra-oral swelling, varied in consistency from extremely firm to fleshy and released mucinous material. The majority of tumours consisted of numerous clumped toothlets, but some included hardened tissues. Local area invasion/transmission was observed in most cases; however, necropsy examination revealed no gross evidence of distant metastasis into visceral organs. Radiographic examination of compound odontomas revealed distinct unilocular radio-opaque mini-toothlets surrounded by defined radiolucency, whereas complex odontomas exhibited unilocular and indistinct radio-opaque masses within a much more extensive radiolucent zone. Histopathologically, the intra-oral tumour lesions were characterized by numerous imperfect (germ) toothlets consisting of a disorganized combination of dental tissues: pulp tissues with manifested and predominantly mixed hard dental tissues of immature dentine and enamel, numerous small to large and round to polyhedral ossicles embedded in hypocellular fibrous stromal tissues and sparsely spaced bland spindloid cells with cleft-like spaces of loose mucoid stroma. Histochemically, the neoplastic lesions stained positive for periodic acid-Schiff and Masson's trichrome. Based on the clinical and histological findings, the tumours were diagnosed as compound odontomas, complex odontomas, odontogenic myxomas, lingual myxomas and psammomatoid ossifying fibromas.

Ameloblastoma in a wild black rat snake (Pantherophis alleghaniensis)

Reports of neoplasia in captive reptiles are becoming more frequent; however, there is still scarce knowledge of the occurrence of neoplasia in wild reptiles. A wild black rat snake (Pantherophis alleghaniensis) was presented to the Zoological Medicine service of the University of Georgia's Veterinary Teaching Hospital with a 3 cm in diameter solid mandibular mass that was partially ulcerated. Radiographically, the mass was radiopaque with small bone spicules and partial osteolysis of the adjacent mandible. Histologic examination of the mass revealed a neoplasm composed of cuboidal to polygonal cells arranged in islands, anastomosing cords, and trabeculae of pseudostratified epithelium with a palisading peripheral layer of densely packed columnar cells with cytoplasmic clearing. The neoplastic tissue was separated from the mesenchyme by a prominent band of fine collagen. Neoplastic cells were positive for cytokeratin and negative for smooth muscle actin. Electron microscopy highlighted the presence of tonofilaments and microvilli. These findings led to the diagnosis of ameloblastoma, an odontogenic epithelial tumor known to occur in humans and most veterinary species.

Pharyngeal odontoma in an adult walleye (Sander vitreus)

An adult walleye (Sander vitreus) was submitted to Cornell University for evaluation of a hard pale-tan pharyngeal mass attached to the gill arches. Dozens of hard white conical structures radiated from the surface. Microscopically, conical structures were identified as denticles and rested on plates of dysplastic orthodentine, cementum, and acellular bone. A diagnosis of compound odontoma was made based upon the presence of proliferative epithelial and mesenchymal odontogenic tissues that recapitulated tooth structures normally present on gill rakers. Odontomas are classified as hamartomas and typically develop in immature diphyodont mammals. The pharyngeal location and lifelong regeneration of teeth in fish, however, both qualify the present diagnosis in the pharyngeal region of an adult teleost. Ontogenic and morphologic differences between mammalian and piscine dentition and differentials for tooth-bearing tumors in fish are presented within the context of a developmental anomaly.

Proceedings of the 2011 National Toxicology Program Satellite Symposium

The 2011 annual National Toxicology Program (NTP) Satellite Symposium, entitled "Pathology Potpourri," was held in Denver, Colorado in advance of the Society of Toxicologic Pathology's 30th Annual Meeting. The goal of the NTP Symposium is to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers' presentations, including diagnostic or nomenclature issues that were presented, along with select images that were used for audience voting or discussion. Some lesions and topics covered during the symposium include: proliferative lesions from various fish species including ameloblastoma, gas gland hyperplasia, nodular regenerative hepatocellular hyperplasia, and malignant granulosa cell tumor; spontaneous cystic hyperplasia in the stomach of CD1 mice and histiocytic aggregates in the duodenal villous tips of treated mice; an olfactory neuroblastoma in a cynomolgus monkey; various rodent skin lesions, including follicular parakeratotic hyperkeratosis, adnexal degeneration, and epithelial intracytoplasmic accumulations; oligodendroglioma and microgliomas in rats; a diagnostically challenging microcytic, hypochromic, responsive anemia in rats; a review of microcytes and microcytosis; nasal lesions associated with green tea extract and Ginkgo biloba in rats; corneal dystrophy in Dutch belted rabbits; valvulopathy in rats; and lymphoproliferative disease in a cynomolgus monkey.