Beyond classic dermoscopic patterns of dermatofibromas: a prospective research study

Abstract

Background: The usual stereotypical dermoscopic pattern associated with dermatofibromas is a pigment network and central white patch. However, this pattern may be difficult to diagnose in some variant cases. We aimed to describe dermoscopic patterns of dermatofibroma according to its histopathological subtypes, with special emphasis on new and rare dermoscopic features.

Methods: This prospective study, which was conducted between September 2015 and May 2016 in the Department of Dermatology, University Hospital Hassan II, Fez, Morocco, included 100 cases of dermatofibroma confirmed on clinical and histological grounds. Each lesion was scored for classic, previously reported, or new dermoscopic features.

Results: All our Moroccan patients had a dark skin phototype (Fitzpatrick scale types IV and V). A total of 14 morphological dermoscopic structures were distinguished, and 17 dermoscopic patterns were observed, with the most common pattern being the central white patch and peripheral pigment network (21%). New patterns observed in our study were a white ring around an ulceration (6%), a pigment network with a pigmented ring around follicular openings (2%), and a discreet peripheral network and starlike white patch (3%). A patchy network with white patches was significantly noted in atrophic dermatofibroma (p = 0.01); vascularization was described in both aneurysmal and hemosiderotic dermatofibromas (p = 0.002); and a white ring around an ulceration was noted in aneurysmal dermatofibroma (p < 0.001).

Conclusions: We provide a description of dermoscopic patterns of dermatofibroma according to its histological subtypes in a dark skin phototype, along with a new report of a white ring around an ulceration as a significant pattern in aneurysmal dermatofibroma.

Keywords: Dermatofibroma; Dermoscopy; New dermoscopic patterns; Rare dermoscopic patterns; Variants.

Fig. 1

a, b, c, d Before immersion. e, f, g, h After immersion: better visualization of pigmented structures as peripheral network globules (e, f), pigmented streaks (g), and an inverted network (h)

Fig. 2

a-d Classic dermoscopic patterns of common fibrous dermatofibroma: pigment network and central scarlike white patch with central globule-like structures

Fig. 3

Previously reported dermoscopic patterns of common fibrous dermatofibroma. a, b Lentigo-like pattern. a Dark phototype. b Clear phototype. c, d Peripheral ringlike structures with central white scarlike appearance. e, f Seborrheic keratosis-like pattern. g, h Multicomponent pattern. i Peripheral pigment network and central inverted network. j Total scarlike patch. The vertical lines in panel c are the measuring lines of the dermlite dermoscope

Fig. 4

a, b, c Dermoscopic patterns of hemosiderotic dermatofibroma: pink bluish pigmentation with the presence of dotted vessels and comma-like vessels. d, e, f Dermoscopic patterns of atrophic dermatofibroma: patchy network and multiple white patches

Fig. 5

News dermoscopic patterns of CFDF. a Total homogeneous pigmentation with white structures forming a ring (black arrow), b, d Pigmented network with a ring around the follicular openings (red arrow). c Discreet peripheral network and star like white patch

Fig. 6

New dermoscopic patterns of aneurysmal dermatofibroma: a-f: white ring around an ulceration with the presence of linear irregular vessels and dotted vessels. The horizontal lines in (e) are the measuring lines of the dermlite dermoscope