Collagenous fibroma (desmoplastic fibroblastoma): a distinctive fibroblastic soft tissue tumor.

Collagenous fibroma is a distinct, benign, fibroblastic/myofibroblastic proliferation, probably neoplasm. It is a slow-growing tumor arising in predominantly subcutaneous tissue. This tumor is composed of stellate-shaped fibroblasts and abundant interstitial collagen. Since none of reported collagenous fibromas recurred, simple excision is an appropriate treatment. Collagenous fibroma should be differentiated from fibromatosis, which has a high risk of local recurrence if simple local excision is done. Fibromatosis is more cellular and shows short fascicular arrangements of tumor cells and greater infiltration at the periphery than collagenous fibroma.