Linear lichen planus pigmentosus of the forehead treated by neodymium:yttrium–aluminum–garnet laser and topical tacrolimus

often seen on the volar aspect of the wrists, the lumbar region and around the ankles. Flexural sites like axillae, groins and inframammary regions may be rarely involved in typical lichen planus. Reports on flexural LP in the published work are either associated with LP pigmentosus or erosive variants. In most LP cases, the papule lesions eventually flatten after a few months, often to be replaced by an area of pigmentation that retains the shape of the papule and persists for months or years. In this case, we can see three kinds of different period lesions (violaceous-brown papules, papules with the pitchy edge and annular dark brownish macules) on the flexural sites representing the gradual regression. Follicular lesions usually appear during the course of typical LP, sometimes as sole manifestation of the disease in the scalp. But they rarely occur in flexural LP. Gunduz et al. reported the first case of combination of follicular and flexural variants of LP. But there was a little difference between the two cases because the follicular lesions localized to the flexures and the waist, respectively. The infiltrating cells in LP are predominantly T-lymphocytes with very few B-lymphocytes. The identification of various subtypes of T-lymphocytes has given contradictory results with regards to the predominance of CD4 helper-inducer T-lymphocytes and CD8 suppressor-cytotoxic T-lymphocytes in the infiltrate. It is likely that both subsets participate in the immunological reaction. Our immunohistochemical study demonstrated the same result and it was easy to distinguish with LP-like keratosis because CD4 lymphocytes were abundant in the dermis as Jang et al. observed. Contrasted to the flexural lesion, the follicular lesion of the waist was characterized by a higher CD4 ⁄ CD8 ratio of T-lymphocytes. Our patient did not use any special treatment in the 6-month course of disease, but we can see the submammary and groin lesions are undergoing progressive spontaneous regression. We conclude that the process is benign and tends to resolve spontaneously. We are now following up the patient without administering any special treatment.