Uterine fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) with COL1A1::PDGFB fusion and concurrent TP53/ERBB2 mutations: Case report and molecular characterization
Uterine dermatofibrosarcoma protuberans (DFSP) with COL1A1::PDGFB fusion is an exceptionally rare sarcoma, and its high-grade variant remains poorly characterized. We reported a 39-year-old Chinese woman with a high-grade uterine sarcoma exhibiting morphological features of fibrosarcomatous DFSP (FS-DFSP), including spindle cells arranged in storiform and herringbone patterns, focal myoid/epithelioid differentiation, and myxoid changes. Immunohistochemistry revealed variable CD34 expression, focal desmin/SMA positivity, and aberrant p53 overexpression. Targeted next-generation sequencing identified a COL1A1-PDGFB (C5:P2) fusion, a pathogenic TP53 (c.832 C>G; p.P278A) and ERBB2 (c.2524 G>A; p.V842I) mutation. Dual-color fluorescence in situ hybridization confirmed COL1A1-PDGFB fusion. This represented the first report of high-grade uterine DFSP with concurrent TP53 and ERBB2 mutations, expanding the molecular spectrum of this entity and suggesting potential therapeutic implications for dual PDGFR/HER2 inhibition in aggressive cases.