Soft Tissue Tumor with PAK2::RAF1 Kinase Fusion: An Emerging Sarcoma Entity

Abstract: Introduction: Here, we report the first case of a soft tissue tumor with a PAK2::RAF1 fusion. Case Presentation: The patient was an 11-year-old female presenting with a 5 cm intramuscular mass in the lower leg. Microscopic examination revealed a mitotically active spindle cell lesion with monomorphic and moderately atypical cells growing in a patternless pattern with the presence of stromal and perivascular keloidal collagen with focal immunoreactivity for smooth muscle actin and S100; negative stains included cytokeratins, CD34, and caldesmon. Whole genome and RNA sequencing detected a chromosome 3 inversion and a resultant PAK2::RAF1 fusion as well as a CDKN2A homozygous deletion. The patient was treated with neoadjuvant chemoradiotherapy with only minimal response and the tumor was excised surgically. There was no evidence of disease progression at 4 months. Conclusion: This is the first case of a soft tissue tumor harboring a PAK2::RAF1 fusion with histological features in keeping with previous cases of RAF1 and other kinase fusion soft tissue tumors.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Soft Tissue Tumor with PAK2::RAF1 Kinase Fusion: An Emerging Sarcoma Entity ; volume:17 ; number:1 ; year:2024 ; pages:960-965 ; extent:6 ; Case reports in oncology ; 17, Heft 1 (2024), 960-965 (gesamt 6)

Contributors, Places and Time

• Creator: Haglund, Cecilia ; Behrendtz, Mikael ; Hesla, Asle ; Haglund de Flon, Felix

Further information

• DOI: 10.1159/000540581
• URN: urn:nbn:de:101:1-2411272330500.600134475016
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:26 AM CEST