A novel aberration of COL1A1-PDGFB fusion as an insertion in chromosome 15 in one case of dermatofibrosarcoma protuberans involving a rare location.

Dermatofibrosarcoma protuberans (DFSP) is a rare sarcoma of the skin arising from the dermis. Its location is most commonly presented on the trunk of middle-aged adults and rarely on the face. The characteristic genetic aberration in the form of a reciprocal translocation t(17;22)(q22;q13) or a ring fusing the COL1A1 and PDGFB genes is found in 90% of DFSP. We present a case of a 42-year-old man who presented with a DFSP on the left cheek with foci of myxoid- fibrosarcomatous transformation. A conventional chromosomal analysis revealed a complex karyotype without a supernumerary ring chromosome or a linear translocation t(17;22). Comparative genome hybridization (CGH) and fluorescence in-situ hybridization (FISH) revealed the fusion of COL1A1 and PDGFB probes inserted in chromosome 15. This is a unique case of DFSP characterized by a rare body location, unique histopathologic features and novel chromosome COL1A1-PDGFB insertion, and may help guide future diagnostic and patient care modalities. This article is protected by copyright. All rights reserved.