PDGFB and dermatofibrosarcoma protuberans: The morphologic and molecular pathologic findings of vulvar DFSP are quite similar to DFSP in other sites, including the frequent finding of the fusion between collagen type I alpha 1 gene (COL1A1) on chromosome 17 and the platelet-derived growth factor B-chain (PDGFB) gene on chromosome 22 [23, 28].