The Blue Globular Pattern in Dermoscopy

Background: Seborrheic keratosis (SK) is a frequent benign epithelial skin tumor. Generally its diagnosis is clinical, however SK can sometimes clinically simulate a melanocytic lesion; therefore we need dermoscopy to reach a correct diagnosis. Milia-like cysts and comedo-like openings are the common dermoscopic features of SK, but it is not a rare finding that SK can display one or more dermoscopic patterns suggestive of a melanocytic origin. Objectives: We describe a case series of SKs with a blue globular pattern simulating a melanocytic lesion. Methods: We retrospectively evaluated 224 SKs seen during 2011 at the Dermatoscopy Unit of the Department of Dermatology, University of Rome 'Sapienza'. Results: Five SKs showed a blue globular pattern, without the SK main features generally seen in dermoscopy; globules were multiple, round or oval, well-demarcated, small and medium-sized, blue-colored and equally distributed within the lesion. Histopathologic examination was consistent with acanthotic SK. Conclusions: Identification of the blue globular pattern can be helpful for the dermoscopic diagnosis of SK, especially when its common dermoscopic features are absent. Copyright (C) 2013 S. Karger AG, Basel