Expression of nestin in dermatofibrosarcoma protuberans in comparison to dermatofibroma.

Making a differential diagnosis to distinguish dermatofibrosarcoma protuberans (DFSP) from dermatofibroma (DF) is occasionally difficult. In those instances, CD34 and factor XIIIa have been used as valuable differential markers. The histogenesis of DFSP, however, remains uncertain and controversial, although it is generally thought to be a neuromesenchymal neoplasm. Nestin is an intermediate filament protein that was first observed in neuroectodermal stem cells. We investigated the expression of nestin in order to distinguish between DFSP and DF in combination with the use of conventional markers, CD34 and factor XIIIa. The nestin expression was investigated in tissue specimens from 16 DFSP cases and 30 DF cases. The expression of other differential markers such as CD34, factor XIIIa, CD163 and CD10 was also observed in these samples. Fifteen (94%) of 16 cases of DFSP showed the expression of nestin, whereas only four (13%) of 30 cases of DF showed the expression of nestin. Most of the DFSP cases showed a diffuse positive reaction in more than half of the tumor cells. In contrast, DF cases with nestin expression showed a partial positive reaction. Nestin is considered to be a useful and additional marker in combination with CD34, factor XIIIa and CD163 in order to distinguish between DFSP and DF. The frequent expression of nestin in DFSP may therefore indicate that DFSP is derived from putative, multipotent neuromesenchymal cells.