Management of an Extraskeletal Osteosarcoma in an African Hedgehog (Atelerix albiventris)

A 5-year-old female African hedgehog (Atelerix albiventris) was presented with a mass on its left caudodorsal flank and progressive lethargy. A fine-needle aspirate of the mass was suggestive of a malignant spindle cell tumor. After the diagnostic test results were obtained, the mass was surgically removed. Histopathological examination of tissue sections from the mass revealed incomplete excision of an extraskeletal osteosarcoma. Approximately 2 months after surgery, the patient suddenly died. Gross examination at necropsy revealed multifocal nodules within the spleen, liver, and lungs. Histopathology of the tissues that contained the multifocal nodules was consistent with metastatic osteosarcoma, originating from the original extraskeletal soft tissue osteosarcoma on the flank. Incidental uterine leiomyoma was also discovered at necropsy. To the authors' knowledge, this is the first reported attempt at surgical treatment of the rarely documented extraskeletal osteosarcoma in a hedgehog.