Tissue cultures of benign and malignant fibrous histiocytomas: SEM observations.

Four dermatofibromas (DF), 2 dermatofibrosarcomata protuberans (DFSP), 2 atypical fibroxanthmas of the skin (AFX), and one malignant fibrous histiocytoma (MFH) were studied by explant culture technique and scanning electron microscopy. Differences in the cellular atypism, phagocytic activity and motility were observed between histiocyte-like cells extending from a DF and DFSP group and an AFX and MFH group. Such cytological characteristics was maintained during in vitro transformation of the cells into fibroblastic cells. It was concluded that culture behaviors of the cells from each tumor group correlated well with in vivo growth and histologic features. We feel that examination of in vitro morphology of fibrous histiocytomas may prove useful in arriving at a correct diagnosis.