[Dermatoscopic "sky full of stars" pattern in a congenital melanocytic nevus with follicular distribution]

Congenital melanocytic nevus (CMN) is present at birth or appears during the first year of life. Certain dermoscopic features allow differentiation from other pigmented lesions and assessment of its evolution. We report a case of CMN with melanocytic distribution limited to hair follicles, associating dermoscopic findings with reflectance confocal microscopy (RCM).

A 2 year and 7 month old male patient with no relevant medical history presented with a 10 × 7 mm melanocytic macule on the left posterior lumbar region, present since birth. Dermoscopy revealed a central gray-blue area with dark brown globules distributed perifollicularly and radially from the follicular ostium, forming a "sky full of stars" pattern. RCM showed melanocytic proliferation at the dermoepidermal junction, organized in dense aggregates and nests, with a mixed mesh and globular pattern.

Perifollicular aggregates observed on dermoscopy correspond to melanin deposits within follicular openings. The "sky full of stars" pattern, which has been rarely described, may be associated with melanocytes confined to the infundibulum and noncontiguous hair follicles. It is important to differentiate this pattern from the globular pattern, which indicates melanocytic activity. RCM may provide useful information for clinical follow-up.