Linear and whorled nevoid hypermelanosis: dermatoscopic features.

Linear and whorled nevoid hypermelanosis (LWNH) is a pigmentation disorder characterized by macular hyperpigmentation following the lines of Blaschko. Dermatoscopy can be used in the differential diagnosis of this pigmentation disorder. To our knowledge, the dermatoscopic features of pigmented lesions in LWNH have not been described previously. Here, a case of LWNH is discussed together with its dermatoscopic findings. An 11-year-old girl presented to our department with hyperpigmentation along the lines of Blaschko over the entire body. The mental status of the patient was normal and no associated anomaly was detected in the physical examination or genetic analysis. Dermatologic examination revealed a whorled-like configuration of hyperpigmented macules on the neck, trunk, and buttocks, and a linear configuration of hyperpigmented macules, some of which were arranged in a parallel linear fashion on the extremities along the lines of Blaschko. Histopathologic examination confirmed the diagnosis. Dermatoscopic examination revealed linear or circular arrangement of streak-like pigmentations arranged in a parallel manner. This is the first known reported case of LWNH that describes its dermatoscopic findings. Dermatoscopy may be used to facilitate the differential diagnosis of melanotic lesions of this pigmentation disorder.