Lichen planus pigmentosus (LPP) is an uncommon variant of lichen planus that tends to occur in middle-aged individuals with darker pigmented skin. Clinical findings include hyperpigmented, brown to gray-brown macules and patches on sun-exposed areas a...
Lichen planus pigmentosus (LPP) is an uncommon variant of lichen planus that tends to occur in middle-aged individuals with darker pigmented skin. Clinical findings include hyperpigmented, brown to gray-brown macules and patches on sun-exposed areas and, in the rare inversus variant, on the flexural areas and intertriginous zones. The pattern of pigmentation is generally diffuse, although follicular, reticular, and unilateral linear variants have been described. We recently encountered a rare case of LPP developed in flexural area, not in sun-exposed area. A 58-year-old male patient presented with brown macules on the inguinal area for 6 months. One or two dark brown macules first appeared and spread gradually. A physical examination showed multiple, ill-defined, dark brown macules on inguinal area. The dermoscopic finding showed mottled pattern and elevated margin. The incisional biopsy was performed and a diagnosis of LPP was made. The fact that LPP can develop in non-sun-exposed areas as well as sun-exposed ones requires a new hypothesis for the pathogenesis of LPP.