Ewing Sarcoma presenting as a gluteal mass in adult woman: Diagnostic approach and its challenges

Sarcomas of the Ewing family of tumours are aggressive neoplasms occurring in bone and soft tissue of mostly children and young adults. It usually affects male more than female with peak incidence 10 to 15 years of age, and rarely encountered in adults especially in more than 40 years old. It is an aggressive, rare tumour with a tendency toward recurrence after resection and early metastasis.

We reported a rare case of Ewing Sarcoma in a 62-year-old woman who had an unusual clinical presentation. She had right painless buttock swelling only for a month. Magnetic resonance imaging (MRI) revealed soft tissue sarcoma originated from right gluteal muscle. The diagnosis of Ewing sarcoma (ES) was made in a limited diagnostic material in an initial tru-cut biopsy, followed by an excision supported by immunohistochemistry (IHC) and Fluorescent In-Situ Hybridization (FISH).

The purpose of this study is to document ES in an adult woman and its diagnostic challenges in histopathologic perspective.