Dermatofibroma

Key Points
Benign skin growths
Usually found on legs

Dermatofibromas are benign skin growths, often found on the legs. They can grow up to about 1 cm in diameter. The typical apperance is of a round, brownish to purple bump. Dermatofibromas contain scar-like tissue and feel like hard lumps in the skin. Another common term for this is a fibrous Histiocytoma. Although the cause is unknown, there is often a history of minor trauma or injury to the site, possibly denoting a causative role in the development of dermatofibromas.

Synonyms for Dermatofibroma include Dermal Dendrocytoma, Fibrous Dermatofibroma, Fibrous Histiocytoma, Fibroma Simplex, Nodular Subepidermal Fibrosis, and sclerosing Hemangioma.

Differential Diagnosis (Other conditions with similar appearance)

Atypical Mole
Mastocytosis
Basal cell carcinoma
Metastatic Carcinoma of the Skin
Blue Nevi
Neurilemoma
Dermatofibrosarcoma protuberans
Prurigo nodularis
Keratoacanthoma
Spitz nevus
Leiomyoma
Malignant Melanoma

Diagnosis
Key Points

Dermatofibromas are diagnosed by visual inspection, though a biopsy may be taken if the diagnosis is uncertain. They usually dimple inward when pinched, thus giving the appropriately named “dimple sign,” that is highly suggestive of the diagnosis.

Treatment
*Mostly unnecessary

Because dermatofibromas are benign (or harmless), no treatment is necessary in most cases. They can be surgically removed, but removal usually leaves a scar.