Extraskeletal osteosarcoma harboring ETV6::NTRK3 fusion treated successfully with larotrectinib: a case study.

ABSTRACT:

Background

Extraskeletal osteosarcoma (ESOS) is a rare, aggressive mesenchymal tumor with limited therapeutic options and a poor prognosis due to frequent metastases. Identifying targetable genetic alterations could improve treatment outcomes. The objective is to report the first worldwide case of ESOS harboring an ETV6::NTRK3 fusion and describe the clinical response to larotrectinib, a selective TRK inhibitor.

Methods

Case report of a 74-year-old man with a rapidly enlarging, inoperable neck tumor measuring 7.9 ×7.1 ×6.6 cm. The case underwent histopathological, immunohistochemical, and molecular analyses, including targeted RNA sequencing using the Archer Fusion Plex Pan Solid Tumor v2 panel and DNA-based targeted analysis with the Ion Torrent Oncomine Comprehensive Assay

SUBMITTER: Skok K 

PROVIDER: S-EPMC12634677 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature