Case Discussion
Dermatofibroma is a common, benign neoplasm which is a moderately well-circumscribed dermal-based proliferation of spindled to histiocytoid appearing cells. There is often overlying epidermal hyperplasia (seen in this case), but also melanocytic and folliculosebaceous hyperplasia. At the tumour periphery, there is "collagen trapping" by lesional cells. There are numerous variants of dermatofibroma, the most common including aneurysmal fibrous histiocytoma, epithelioid cell histiocytoma and cellular fibrous histiocytoma.
