Primary Ewing’s Sarcoma of Squamous Temporal Bone with Intracranial Extension: A Rare Presentation

A BSTRACT Ewing’s sarcoma (ES) family of tumors is a group of small round cell neoplasms characterized by common chromosomal translocation. Involvement of skull in ES is seen in less than 2% of the cases. To the best of our knowledge, only 2 cases of Primary ES of squamous part of the temporal bone have been reported. A 21-year-old male presented with complaints of pain and swelling in the right temporal region; headache and drooping of eyelids since 1.5months. An extended right pterional craniotomy was performed, and was sent for histopathological study. On microscopy, sections showed a tumor composed of cells in diffuse sheets. Tumor cells have round to oval nuclei with finely dispersed chromatin and scant cytoplasm. Rosette formation noted. On immunohistochemistry, tumor cells were positive for CD99, FLI-1 and Vimentin. Involvement of cranium by ES is very rare. Only 29 cases of primary ES of cranium have been reported and 14 cases pertaining to involvement of temporal bone. Differential diagnosis of such large and progressively increasing mass can be embryonal rhabdomyosarcoma, lymphoma or metastatic neuroblastoma. Though primary cranial ES of temporal bone is rare, it should be kept as differential diagnosis in cases of temporal scalp swelling. ES of temporal bone is a rare entity. Primary ES in skull is reported to have better prognosis compared to elsewhere. Although incidence is low, early diagnosis is essential for better outcome.