Background: Several dermoscopic patterns have been described in dermatofibroma (DF), but little is known about morphologic features of DF in different anatomic locations. The aim of this study was to evaluate the association between the dermoscopic pattern of DF and the anatomic location.
Methods: We conducted a retrospective observational study of 169 DF that were evaluated for the presence of dermoscopic structures and patterns. Patients' age and sex were recorded, while the anatomic location of each lesion was categorized in 2 main groups, namely extremities and trunk. The possible correlation between the dermoscopic pattern and the anatomic site was tested using the χ2 test or the Fisher's exact test, as appropriate.
Results: DFs resulted mainly located on extremities as compared to trunk (79.2% and 20.7%, respectively). Frequencies of dermoscopic patterns of DF were the following: atypical (26.6%), network and patch (23.7%), total structureless (17.1%), structureless and patch (9.5%), total network (6.5%), network and structureless (3.5%), double network (2.9%), white network and total structureless (2.9%), white network (2.9%), multifocal patches (2.4%), and total patch (1.8%). A significant association between network and patch pattern and extremities (27.6%) was found (P<0.05). Similarly structureless and patch pattern resulted completely absent on trunk and quite frequent on extremities (11.9%; P<0.05). In contrast, total structureless was the most common pattern on the trunk (31.4%) and less represented on extremities (P<0.05). Total network pattern followed the same trend (P<0.05).
Conclusions: Our study reveals that the dermoscopic pattern of DF is significantly influenced by the anatomic location of the lesion. The "classic" pattern with a white patch surrounded by network dermoscopically characterizes DFs of the extremities, while DFs located on the trunk often exhibit different findings.