A clinical and histopathological study of 122 cases of dermatofibroma (benign fibrous histiocytoma).

BACKGROUND Many variants of dermatofibromas have been described, and being aware of the variants of dermatofibromas is important to avoid misdiagnosis. OBJECTIVE We wanted to evaluate the clinical and pathologic characteristics of 122 cases of dermatofibromas. METHODS We retrospectively reviewed the medical records and 122 biopsy specimens of 92 patients who were diagnosed with dermatofibroma in the Department of Dermatology at Eulji Hospital of Eulji University between January 2000 and March 2010. RESULTS Nearly 80% of the cases occurred between the ages of 20 and 49 years, with an overall predominance of females. Over 70% of the lesions were found on the extremities. The most common histologic variant was a fibrocollagenous dermatofibroma (40.1%). Other variants included histiocytic (13.1%), cellular (11.5%), aneurysmal (7.4%), angiomatous (6.5%), sclerotic (6.5%), monster (4.9%), palisading (1.6%) and keloidal dermatofibromas (0.8%). There were 9 dermatofibromas (7.3%) that were the mixed type with two co-dominant histologic features. CONCLUSION The results of this study are consistent with previous reports on the clinical features of dermatofibromas. However, we observed several characteristic subtypes of dermatofibroma and we compared the frequency of the histologic subtypes.