Multiple dermatofibromas: dermoscopic patterns

Abstract

Dermatofibromas are benign skin lesions that consist of pigmented papules or nodules. They produce the dimple sign when laterally squeezed and are usually found on the legs. These clinical features lead to the diagnosis in most cases. However, the differential diagnosis with other lesions, such as atypical nevi and melanoma can be difficult, and the dermoscopy may help the diagnosis. There are several dermoscopic patterns associated with dermatofibromas, the most common being a central white scar like patch with delicate pigment network at the periphery. This article describes the case of a patient who had eleven clinically similar dermatofibromas, with four distinct patterns when submitted to dermoscopic examination.

Keywords: Benign fibrous; dermoscopy; histiocytoma; skin and connective tissue diseases; skin diseases.

Figure 1

Dermatological examination. Eleven papularnodular brownish lesions, ranging from 5 to 10 mm in diameter, were found on the trunk, buttocks and lower limbs

Figure 2

H and E, ×40. Dermatofibroma. Hyperplastic epidermis with hyperpigmentation of the basal layer and elongated epidermal ridges. Proliferation of fibroblast like spindle cells in the dermis, separated from the upper epidermis by a Grenz zone. This dermal tumor has poorly defined margins and trapped collagen bundles on the periphery of the lesion, ×400. Fibroblast like spindle cells

Figure 3

Dermoscopy. First pattern. Delicate peripheral pigment network with central globule like structures

Figure 4

Dermoscopy. Second pattern. Irregular crypts and pseudofollicular openings

Figure 5

Dermoscopy. Third pattern. Homogeneous pigmentation

Figure 6

Dermoscopy. Fourth pattern. Central irregular white scarlike patch with pseudofollicular openings and a peripheral erythematous homogeneous macule