Dermoscopy findings of a one mm lentigo maligna

Abstract

A 66-year-old man presented with a grayish 1mm macule on the left cheek. Dermatoscopic examination revealed annular-granular structures partially surrounding a single follicular ostium. Histopathologic examination demonstrated atypical, confluent single melanocytes at the basal layer with nesting, crowding, and upward migration descending along the hair follicle, consistent with the diagnosis of lentigo maligna (LM). This case presents evidence in support of the Schiffner progression model for LMs, starting with asymmetric pigmented follicular openings composed of annular-granular structures, which later coalesce into gray to dark black/brown streaks, and then form pseudo-networks or rhomboidal structures. The finding of annular-granular structures partially surrounding a single hair follicle may be the earliest recognizable dermatoscopic feature of an LM and may help clinicians diagnose facial LMs earlier.