RESUMO
Osteosarcomas are unusual neoplasms in African hedgehogs ( Atelerix albiventris ) and have been reported in extraskeletal and skeletal locations, including mandible, ribs, and vertebra. Five hedgehogs with osteosarcoma submitted to the Pathology Department at Facultad de Medicina Veterinaria y Zootecnia, National Autonomous University of Mexico are reported. In two cases, the neoplasm arose from the skull; one case arose from the ribs with associated compression of the thoracic and abdominal cavity, and another case involved the vertebrae. In the last case, the neoplasm arose from the scapula. Histologic lesions were similar in all cases and consisted of well-demarcated nodules in which neoplastic cells were arranged in sheets of polyhedral to spindle-shaped cells with interspersed areas of necrosis. Numerous trabeculae of osteoid were present throughout the tumors. No metastases were detected. The predominant histologic pattern was osteoblastic, but a telangiectatic-like pattern was observed in the vertebral osteosarcoma. Electron microscopy was performed in two cases, and malignant osteoblasts had features consistent with descriptions in other species, including deposits of hydroxyapatite in osteoid. According to these cases and previously published data, axial osteosarcomas are more frequent in contrast to appendicular osteosarcomas in African hedgehogs, and metastases are rare.