Possible role of the collagen type I alpha 1-platelet-derived growth factor beta chain fusion gene in the development of dermatofibrosarcoma protuberans with fibrosarcomatous transformation

Dermatofibrosarcoma protuberans with fibrosarcomatous transformation (DFSP-FS) is a rare variant, with higher rates of recurrence and metastasis than DFSP. Detection of the collagen type I alpha 1 (COL1A1)-platelet-derived growth factor beta chain (PDGFB) fusion gene is useful for the diagnosis of DFSP. In this letter, we report a case of DFSP-FS, focusing on the expression of the COL1A1-PDGFB fusion gene in the lesions. Increased expression of the COL1A1-PDGFB fusion gene may be associated with fibrosarcomatous changes during the pathogenesis of DFSP.