Synchronous epithelioid sarcoma of bilateral thigh: a rare case report and literature review

Epithelioid sarcoma(ES) is an exceedingly rare soft-tissue sarcoma, accounting for approximately 1% of all soft-tissue sarcomas. Despite its typically indolent clinical course, ES carries a substantial risk of local recurrence and distant metastasis, underscoring the importance of early recognition. However, diagnosis is often delayed because clinical suspicion is low and ultrasonography(US)/magnetic resonance imaging(MRI) are frequently nonspecific. In this report, a 47-years-old woman was admitted after incidentally noticing egg-sized masses on the medial aspects of both mid-thighs for one week. Lower Extremity US and Lower Extremity MRI both failed to correctly diagnose the bilateral thigh tumors. Histopathological examination demonstrated malignant tumors arising from skeletal muscle in both thighs. Immunophenotypic findings confirmed a diagnosis of classic-type ES. We further review the literature to summarize the clinical and US/MRI characteristics of ES and to highlight diagnostic pitfalls and current therapeutic strategies.