Dermatofibroma: a possible model of local fibrosis with epithelial/mesenchymal cell interaction.

Dermatofibromas are benign dermal nodules usually seen on the extremities; however, whether a dermatofibroma is a reactive fibrous hyperplasia or a true neoplasm is still unclear. Fibrous type dermatofibromas might be regarded as the symptom of local fibrotic processes and thus present a possible model of local fibrosis. Interaction between proliferated dermatofibroma fibroblasts and overlying elongated epidermis suggests a relationship between keratinocytes and mesenchymal cells. We herein describe current insights into the pathogenesis of dermatofibromas and explore the possible involvement of immunocytes around fibroblasts and effector cells which play an important role in the development of dermatofibromas.