This study was registered at the German Clinical Trial Register (DRKS-Study-ID: DRKS00013570; https://www.drks.de/drks_web/).

This study provides evidence for the existence of a subgroup of slow-growing melanomas, which may explain the increase in the incidence of thin melanoma, despite stable rates of thick melanoma and melanoma-associated mortality.

The data collected provide a new knowledge regarding the clinical and dermoscopy features of pigmented scalp tumours.

We identified RCM criteria for diagnosis of LPLK that correlate well with histopathological findings and that allow differentiation of LPLK from skin cancer.

Reference1 Cheng ST, Ke CL, Lee CH et al. Rainbow pattern in Kaposi's sarcoma under polarized dermoscopy: a dermoscopic pathological study. Br J Dermatol 2009; 160:801-9.