Aggressive high-grade Ewing's sarcoma of maxilla: A rare case report.

Ewing's sarcoma (ES) is an uncommon malignancy of childhood and adults that constitutes 6%-8% of all primary malignant tumors and the third-most common tumor after osteosarcoma and chondrosarcoma, frequently involves the mandible among jaw bones. This article presents a rare case of ES of maxilla in a 22-year-old male patient showing extensive lesion into skull base which was confirmed with computed tomography, dilemmatic histopathologic features in H and E which is not a frequent presentation. Histopathologic features showed monotonous round cells with hypo- and hyper-cellular areas, intralesional hemorrhage and necrosis with lesional cells positive for CD99. Although the prognosis is poor, early diagnosis and long-term follow-up can improve the survival. The diagnosis was confirmed by immunohistochemistry where lesional cells were positive for CD 99 and vimentin. ES of maxilla is a rare and aggressive tumor. Hence, early diagnosis, combined therapy, and long-term follow-up are suggested in such cases.