Ameloblastoma in a wild black rat snake (Pantherophis alleghaniensis)

Abstract

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.

A dinosaurian facial deformity and the first occurrence of ameloblastoma in the fossil record

“…The presence of this benign neoplasic modification is reported here for the first time in the dinosaurian fossil record, as well as in the fossil record overall. The occurrence of ameloblastoma is a well-known phenomenon in humans 37 and other mammals 38 , yet has only recently been identified among reptiles in the living wild black rat snake 39 . A related disorder, adenoameloblastoma, was noted in the Indian rock python 40 .…”

A comprehensive diagnostic approach combining phylogenetic disease bracketing and CT imaging reveals osteomyelitis in a Tyrannosaurus rex

“…The skeletal tumours that have been identified are the following: osteoma, ameloblastoma, ossified fibroma, osteosarcoma, osteochondroma and chondrosarcoma 40,41,55,77,80 . Studies have shown malignant entities to be dominant among neoplasms in NARs, at approximately 80% of all diagnosed neoplasms (83.3% in Page-Karjian et al, 76% in Ramsay et al) 81,82 .…”

Dentinogenic Ghost Cell Tumor in a Sumatran Rhinoceros

“…Diagnosis of DGCT in this rhinoceros was largely made based on the histological and immunohistochemical features from human oncology and pathology as compiled in Table 1 . From the differential diagnoses, PIOSCC, SCC and ameloblastoma were ruled out, as these tumors do not feature ghost cell lesions [ 12 ]. GCOC was ruled out mainly by the fact that histopathological examination showed low mitotic activity, suggestive of a benign cellular status.…”