Ewing sarcoma of the frontal sinus in an elderly patient: a case report and review.

Ewing sarcoma is a malignant small round cell tumor with an aggressive clinical course that typically arises in the extremities or trunk of adolescents and young adults. Sinonasal Ewing sarcoma in elderly patients is extremely rare, and its diagnosis can be challenging owing to overlapping histopathological features with other malignancies. A 71-year-old woman with a sinonasal tumor was referred to our hospital. The initial pathological diagnosis based on an outpatient biopsy was olfactory neuroblastoma (ONB). However, the absence of tumor in the olfactory cleft suggested other histological types. A surgical biopsy was performed, and Ewing sarcoma was confirmed by immunostaining and fluorescence in situ hybridization. One month after surgical biopsy, rapid tumor growth with intracranial extension was observed. Chemotherapy and extensive skull-base surgery were declined. Although carbon-ion radiotherapy was effective for the primary tumor, bone metastases developed shortly after treatment, and the patient died 7 months after the initial visit. This case highlights the diagnostic pitfalls of sinonasal malignancies and the importance of endoscopic and radiologic findings as potential diagnostic clues. In frontal sinus Ewing sarcoma, local treatment alone is unlikely to achieve cure without chemotherapy. However, the standard regimen for Ewing sarcoma is often too toxic for elderly patients, underscoring the need for more tolerable treatment options. To our knowledge, this is the first reported case of frontal sinus Ewing sarcoma in a patient over 60 years old.