Primary Ewing sarcoma of the squamous temporal bone with intracranial and extracranial extension: A rare cause of sudden sensorineural hearing loss.

Primary Ewing sarcoma of the cranial bone is rare, accounting for only 1% of all Ewing sarcomas. Primary Ewing sarcoma arising in the squamous temporal bone is particularly rare.A 16-year-old male was seen with signs of sudden sensorineural hearing loss (SSNHL). After 1 week of SSNHL and new-onset headache, imaging studies showed a mass that originated in the left squamous temporal bone with intracranial and extracranial extension. Histopathological study revealed that the mass was a Ewing sarcoma.The patient manifested the diagnostic EWSR1 mutation and was treated with adjuvant multidrug chemotherapy and focal radiotherapy after surgery according to the Children's Oncology Group interval compression arm of AEWS0031 with a regimen of vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide/etoposide.This case showed an extremely uncommon location, as well as unusual symptoms of primary Ewing sarcoma.