Dermatofibrosarcoma protuberans of the face: A clinicopathologic and molecular study of 34 cases.

Abstract

Dermatofibrosarcoma protuberans (DFSP) is one of the most common dermal sarcomas, but facial DFSP is rare. The clinicopathological characteristics of 34 facial DFSPs were reviewed. Additional immunostaining (CD34) and PDGFB/COL1A1-PDGFB fluorescence in situ hybridization (FISH) detection were performed. Patients were aged from 24 to 64 years (mean 42.9 years), with a male-to-female ratio of 4.7: 1. Morphologically, classic DFSP (25/34, 73.5%), pigmented DFSP (2/34, 5.9%), DFSP with myoid differentiation (1/34, 2.9%) and fibrosarcomatous DFSP (FS-DFSP) (6/34, 17.6%) were found. Moreover, myxoid degeneration was observed in three FS-DFSP cases (3/6, 50.0%). All 29 cases that underwent CD34 immunohistochemistry exhibited positive staining (100%). Genetically, PDGFB rearrangement/COL1A1-PDGFB fusion was detected in 94.1% (16/17) of patients. Regarding prognosis, the recurrence (83.3% vs. 59.1 %) and metastasis (33.3% vs. 0%) rates were higher in FS-DFSPs than that in ordinary DFSPs. All available surgical margins were positive before DFSPs recurrence. All patients with negative excision or re-excision margins were alive without evidence of disease (mean, 81.8months; median, 81months). Facial DFSP occurs predominantly in males, while FS-DFSPs are more likely to exhibit myxoid degeneration and a worse prognosis. Notably, negative surgical margin status determined a satisfactory prognosis.