Ewing Sarcoma of the Maxilla: An Uncommon Anatomical Presentation in a Young Patient.

Ewing sarcoma (ES) of the maxilla is an exceptionally rare entity that can mimic odontogenic or inflammatory conditions, often resulting in diagnostic delay. We report the case of a 23-year-old female who presented with a painless, progressively enlarging swelling of the anterior maxilla. Imaging demonstrated an expansile osteolytic lesion with cortical disruption. Histopathologic evaluation revealed a small round cell neoplasm, and immunohistochemical analysis showed diffuse membranous expression of cluster of differentiation 99 (CD99) and focal nuclear positivity for Friend leukemia integration 1 (FLI-1), supporting the diagnosis within the ES family of tumors in the appropriate clinicoradiologic context. The patient underwent subtotal maxillectomy with intraoperative margin assessment, achieving complete surgical excision with histologically negative margins, followed by adjuvant chemotherapy with epirubicin, cisplatin, and ifosfamide, as well as localized radiotherapy. At 18 months of clinical and radiologic follow-up, there was no evidence of local recurrence, with preserved oral function and satisfactory aesthetic outcomes on clinical evaluation. This report highlights the importance of considering malignant small round cell tumors in rapidly enlarging maxillofacial lesions and emphasizes the role of multidisciplinary management in achieving sustained local disease control while preserving postoperative function.