DERMATOFIBROMA
DERMATOFIBROMA ICD-10: D23-L62
• A dermatofibroma is a very common, button-like dermal nodule, usually occurring on the extremities.
• Important only because of its cosmetic appearance or its being mistaken for other lesions, such as malignant melanoma when it is pigmented.
• Considered to represent late histiocytic reaction to an arthropod bite.
• Asymptomatic nodule (Fig. 9-48), 3 to 10 mm in diameter, domed but also sometimes depressed below surrounding skin. Surface dull, shiny, or scaly. Firm, color variable— skin-colored, pink (Fig. 9-48A), brown or dark chocolate brown (Fig. 9-48B); borders ill defined. Dimple sign: lateral compression produces a “dimple” (Fig. 9-48C).
• Rarely may be tender.
• Appears gradually over several months and persists without further increase in size for years
• Treatment not necessary, but can consider surgical excision.
A
B C
FIGURE 9-48 • Dermatofibroma (A) A dome-shaped, slightly erythematous and tan nodule with a button-like, firm consistency. (B) This lesion is pigmented. Can be confused with blue nevus or even nodular melanoma. The pigment is melanin and hemosiderin. (C) “Dimple sign.” Dimpling of the lesion is seen when pinched between two fingers.