Dermoscopy of Dermatofibroma

Overview / Definition A dermatofibroma (DF) is a common, benign skin tumor derived from fibroblasts. It typically presents as a firm, elevated nodule in the dermis and is often asymptomatic. These lesions are frequently found on the lower extremities of adults and are characterized by their distinctive dermoscopic features. Epidemiology Dermatofibromas are among the most common benign skin tumors. They occur predominantly in adults, with a higher incidence in females than males. The age of presentation usually ranges from 20 to 50 years. Incidence is approximately 0.6% to 4% in the general population. More frequently found in females. Commonly located on the lower extremities. Pathophysiology / Mechanism The exact cause of dermatofibromas is unknown, but they are thought to arise from a reactive process to trauma, such as insect bites or minor injuries. Histologically, dermatofibromas consist of spindle-shaped fibroblasts, foamy macrophages, and collagen deposition. Clinical Presentation Dermatofibromas typically appear as: Firm, raised nodules ranging from 0.5 to 1.5 cm in diameter. A brownish color, which can vary from tan to dark brown. A characteristic “dimple sign”; when pinched, the center of the nodule depresses. While asymptomatic, they may occasionally itch or be tender. Diagnosis / Workup Diagnosis of dermatofibroma is primarily clinical, supported by dermoscopy: Dermoscopy findings: Central ulceration or fibrinous crust. Peripheral brownish pigmentation. White scar-like areas (fibrotic areas). Vascular structures may be seen, including telangiectasias. In uncertain cases, a biopsy may be warranted to rule out malignancy, especially if the lesion exhibits atypical features. Treatment / Management Dermatofibromas are usually benign and do not require treatment unless symptomatic or for cosmetic reasons. Treatment options include: Excisional surgery: Complete removal is the gold standard for symptomatic lesions. Cryotherapy: Effective for small lesions, but