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.