Dermatofibroma

Excerpt

Dermatofibroma is a commonly occurring cutaneous entity usually centered within the skin's dermis. Dermatofibromas are referred to as benign fibrous histiocytomas of the skin, superficial/cutaneous benign fibrous histiocytomas, or common fibrous histiocytoma. These mesenchymal cell lesions of the dermis clinically are firm subcutaneous nodules that occur on the extremities in the vast majority of cases and may or may not be associated with overlying skin changes. They are most commonly asymptomatic and usually relatively small, less than or equal to 1 centimeter in diameter. The term "fibrous histiocytoma" refers more to the morphologic appearance of the cell populations that comprise these lesions rather than strictly describing the cellular lineage.

There are two theories of the genesis of dermatofibromas: (1) reactive process vs. a clonal, and (2) neoplastic proliferation. Evidence exists for both of these theories. Often, patients who present with a dermatofibroma relate a history of possibly inciting local trauma at the site, such as from an insect bite or superficial puncture wound from thorns or wood splinters. Dermatofibromas occur in people of all ages, although more commonly during the ages of the 20s to 40s, and develop more frequently in females than males, with as high as a 2:1 female to male predominance according to some reports. They are a benign tumor, although there have been cases of local recurrence, and even more rarely, distant metastases have been reported. When considering the differential diagnosis of these lesions, it is vitally important to distinguish dermatofibromas from dermatofibrosarcoma protuberans, a similar-appearing but more aggressive cutaneous neoplasm.