Mandibular primitive neuroectodermal tumor in an adult dog

This is the report of a mandibular neuroectodermal/ewing sarcoma in an 8-year-old male cross breed dog that is unique because of tumor origin location. Pedunculated، ulcerative، firm 6. 0 × 4. 0 × 5. 5 cm tumor mass effaced the bone at the rostral part of the mandible and had a white-sanguineous color at cross section appearance. Histopathologically، small round blue cell tumor was diagnosed. Immunohistochemically، tumor cells were positive for vimentin، S100 and Glial fibrillary acidic protein (GFAP) and negative for neuron specific enolase (NSE) and desmin. Mandibular location is a rare event in these types of tumors.