Dermatofibroma
Dermatofibroma, also called benign fibrous histiocytoma, is a common firm dermal papule of the extremities that arises from proliferation of benign spindle cells, often after minor local trauma, and characteristically dimples inward when pinched. Diagnosis is clinical, and no treatment is required for asymptomatic common lesions, though cryotherapy with liquid nitrogen is a reasonable option for patients who want a lesion addressed for cosmetic reasons.
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What this article covers
- Overview
Definition: dermatofibroma, also known as benign fibrous histiocytoma, is a common benign soft tissue lesion caused by proliferation of spindle cells within the dermis.
- Epidemiology
Age of onset: dermatofibroma typically appears in early to mid-adulthood, most often between 20 and 40 years of age, though it can occur in any age group, including children.
- Risk factors
Local cutaneous trauma: many dermatofibromas are thought to be a reactive process following minor trauma such as an insect bite, a puncture wound from a splinter, or an ingrown hair.
- Pathophysiology
Debated origin: the exact pathogenesis is unknown and remains debated between two models.
- Clinical features
Defining appearance: a slow-growing or static, firm, dermal papule that is pink or tan-brown to black in color, most often under 2 cm in diameter and most commonly located on the limbs.
- Differential diagnosis
Dermatofibrosarcoma protuberans: a locally aggressive, slow-growing tumor that can mimic dermatofibroma, especially early on, but is typically larger (average size over 5 cm) and unlike benign…
- Diagnosis
Clinical diagnosis anchored by the dimple sign: the diagnosis is usually made from appearance and history alone; a firm papule on an extremity that dimples centrally on lateral pinching in a patient…
- Management
First, reassure and observe for a typical, asymptomatic, static, common dermatofibroma: no treatment is required, since surgical excision typically leaves a scar that looks worse than the original lesion.
- Complications
Cosmetic dissatisfaction: the main practical concern for most patients, since common dermatofibromas are asymptomatic and medically benign.
- Prognosis
Excellent for common dermatofibroma: lesions are usually benign, static, and asymptomatic, with little to no growth over time.
- Prevention
No established primary prevention: because the pathogenesis is debated and many lesions may follow minor unrecognized trauma, there is no specific measure known to prevent a common dermatofibroma from forming.
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