Dermoscopy of dermatofibromas: a prospective morphological study of 412 cases

Abstract

Objective: To describe the dermoscopic features, including vascular structures and patterns associated with dermatofibromas in a large series of cases.

Design: Digital dermoscopic images of the prospectively collected dermatofibromas were evaluated for the presence of multiple structures and patterns.

Settings: Dermatofibromas were collected in the Departments of Dermatology of the Hospital de Sant Pau i Santa Tecla, Tarragona, Spain, and Hospital de Sant Llatzer, Palma de Mallorca, Spain.

Patients: A total of 412 dermatofibromas (from 292 patients) with complete documentation were collected.

Main outcome measures: Frequency and intraobserver and interobserver agreement of the dermoscopic structures and patterns in dermatofibromas.

Results: A total of 19 morphological dermoscopic structures were evaluated. Pigment network was observed in 71.8% (3% atypical pigment network), white scarlike patch in 57.0%, and a white network in 17.7%. Different vascular structures were observed in 49.5% (dotted vessels in 30.6%). Ten dermoscopic patterns were observed. The most common pattern seen in our series (34.7% of cases) was central white patch and peripheral pigment network, but in 65.3% of the cases, dermatofibromas presented different patterns including simulators of melanoma.

Conclusion: The most common pattern associated with dermatofibroma is the classic dermoscopic pattern (pigment network and central white patch), but this tumor has a wide range of presentations.