Intratumoral mast cell number is negatively correlated with tumor size and mitosis in dermatofibrosarcoma protuberans

Abstract

Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous tumor with intermediate malignancy. The purpose of this study was to evaluate the utility of p53, smooth muscle actin (SMA) and c-kit as immunohistochemical markers and toluidine blue staining for mast cell that can correlate with the clinical outcome and clarify role of mast cells in pathogenesis of tumor. We analysed data for 32 lesions from 31 patients. Fibrosarcomatous type DFSP showed high immunoreactivity for SMA compared with other subtypes (P = 0.026). No differences in p53 immunoreactivity were observed between subtypes. None of tumor cells were immunoreactive with c-kit. The mast cell counts showed a negative correlation with mitosis and tumor size (P < 0.05), implying that mast cells do not have a causative primary role in tumorigenesis but rather play a secondary role.