A Rare Case of Ewing Sarcoma of the Maxilla and a Literature Review of Similar Cases.

Ewing sarcoma (ES) is a small, round, blue cell malignant neoplasm that rarely occurs in the craniofacial skeleton, with presentation in the maxilla being exceedingly rare. We report the case of a 14-year-old girl with a two-year history of slowly progressive facial swelling that has recently become greatly enlarged. Imaging revealed an aggressive expansile left maxillary lesion with soft-tissue involvement and internal calcifications. Surgical resection was performed, and histopathological analysis showed sheets of homogenous round cells with minimal cytoplasm and round nuclei. Immunohistochemical staining for CD99, CD56, and NKX2.2 was positive, while staining for epithelial, muscle, and neural markers was negative, thereby confirming the diagnosis of ES. This case highlights the diagnostic difficulty of ES in unusual sites such as the maxilla, where it can mimic odontogenic or fibro-osseous lesions. Early diagnosis with histopathology and immunohistochemistry is important for appropriate management, which usually includes surgical resection followed by chemotherapy.