Two cases of dermatofibroma with atypical clinical features

Abstract

Dermatofibroma is a common benign fibrohistiocytic tumor with a propensity for the lower extremities and this manifests with firm, indolent nodules. However, dermatofibroma may show a wide variety of clinicopathologic variants and so it is often misdiagnosed. We experienced two patients who showed atypical clinical features of dermatofibroma. The first case was a 35-year-old female who presented with a 3-month history of a solitary skin-colored hyperkeratotic nodule on the right palm. She had past history of recurrence after laser ablation at a private hospital. The second case was a 66-year-old female who presented with a 3-year history of a solitary brownish irregular shaped atrophic plaque on the right thigh. Histopathologic examination of both patients' lesions revealed poorly circumscribed nodular tumor composed of collagen bundles, fibroblasts and histocytes, and this was all consistent with dermatofibroma. From these finding, we diagnosed these cases as dermatofibroma. Clinical awareness may be the first step to identify the patients with the various features of dermatofibroma.