Ewing's sarcoma of the mandible

Ewing's sarcoma is a malignant tumor of bones that primarily affects children and young adults. The true origin of this small round cell lesion still remains controversial. It was originally described by James Ewing in 1921 as arising from undifferentiated osseous mesenchymal cells; however, recent studies suggest that Ewing's tumor might be neuroectodermally derived from various degrees of differentiation of the primitive neural tissues. This paper reports a rare case of ES of the mandible in an 11-year-old girl, which had been previously misdiagnosed and treated as a dental abscess. In the clinical examination, a hard immobile expansive mass of 2 cm diameter was observed on the left side of the mandible. Radiographic examination revealed a diffuse radiolucent lesion with ill-defined borders and wide vestibular bone plate destruction. Microscopically, the tumor was composed by monotonous small round cells that exhibited immunoreactivity for CD99, vimentin and desmin. Surgical resection of mandible followed by mandibular reconstruction was adopted. The patient was subjected to multiagent chemotherapy with Vincristine [VC], Dactinomycin [AC], Cyclophosphamide [CP] and Doxorubicin [AD]).