Digital dermatofibromas--common lesion, uncommon location: a series of 26 cases and review of the literature.

Dermatofibroma (DF), also referred to as cutaneous fibrous histiocytoma (CFH), is a common tumor of the skin presenting as a firm nodule located predominantly on the limbs and shoulder and pelvic girdles that often extends into superficial subcutaneous tissue. This is a retrospective study of 26 DFs located on digits. All case slides were retrieved from saved files for diagnostic verification. One case was rejected after revision of the diagnosis to giant cell tumor of the tendon sheath. The 26 remaining cases constitute this reported series. Digital DFs affected 27 to 70 year-olds in a 2.25:1 male to female ratio. The most common clinical diagnosis submitted was "growth" or wart. In only 6 out of the 26 cases was the pre-biopsy diagnosis of DF ventured. Although lesional tissue went to dermal margins in 14 specimens, only one has been re-excised in follow up ranging from 2 months to 10 years. Because DFs can resemble several entities including leiomyosarcoma and dermatofibrosarcoma protuberans, a lack of familiarity with the occurrence of DF on the digits may result in more aggressive treatment than otherwise necessary. DF should be in the differential diagnosis of circumscribed, firm nodules presenting on the digits.