EWSR1::BEND2 fusion sarcoma in bone: a report of two rare cases

Çetin S., Ünverengil G., Yılmaz İ., Erdoğan N., ERŞEN DANYELİ A., Salduz A., ...More

Virchows Archiv, vol.486, no.4, pp.877-885, 2025 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 486 Issue: 4
  • Publication Date: 2025
  • Doi Number: 10.1007/s00428-025-04063-z
  • Journal Name: Virchows Archiv
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, CAB Abstracts, CINAHL, MEDLINE
  • Page Numbers: pp.877-885
  • Keywords: Biphasic round/spindle cell morphology, Bone localization, EWSR1::BEND2 fusion sarcoma
  • Acibadem Mehmet Ali Aydinlar University Affiliated: Yes

Abstract

The two cases, we had presented here, were extremely rare instances of the EWSR1::BEND2 fusion sarcomas in bone. The first case was a 12-year-old female with a 50 × 25-mm lytic tumor in metatarsal bone. Histopathologic examination revealed a widespread cellular, fascicular forming, spindled cell component along with a focal round cell component. CD99 was diffuse membranous positive while cytokeratin and EMA were focal positive. The second case was a 62-year-old female with a pathological fracture in femur. On MRI examination, a heterogeneous tumor measuring 96 × 54 mm was detected in the femur, extending into the soft tissue. Histopathologic examination revealed a high-grade lesion consisting of round cells. CD56, CD99, and cytokeratin were focal positive. EWSR1::BEND2 fusion has previously been reported in a subtype of astroblastoma and other rare entities that we discuss in this work.