Atypical Presentation of Lichen Planopilaris: Presentation of Two Cases and Review

Abstract

Lichen Planopilaris (LPP) is an uncommon scalp disorder of unknown etiology and prevalence. It is thought to be an autoimmune process triggered by unknown genetic and/or environmental factors that attack hair follicles of the scalp. LPP has been reported to mimic or present in association with various autoimmune diseases and immunomodulatory therapies. We present two atypical case of LPP in Caucasian patients; the first is a patient with generalized pruritus, skin eruptions, and scalp hair loss. Biopsy of the lesions revealed exocytosis of atypical lymphocytes at the Dermo-Epidermal Junction (DEJ) and formation of small Pautrier’s microabscesses in the interfollicular epidermis as well as a robust lymphocytic inflammatory infiltrate with destruction of perifollicular appendages. This led us to the diagnosis of LPP-like Folliculotropic Mycosis Fungoides (FMF). The second case is a patient with a history of Systemic Lupus Erythematosus (SLE) who presented clinically with perifollicular erythema and alopecic patches, with loss of follicular ostia on the frontal and vertex scalp and evidence of follicular tufting. Histologically, she had decreased number of follicles with a peri-infundibular lymphocytic infiltrate and vacuolization at the Dermoepidermal Junction (DEJ) and there was also thickening of the basement membrane highlighted with a periodic acidic Schiff stain. This led to a diagnosis of SLE/LPP overlap. Keywords: Lichen Planopilaris (LPP); Cicatricial; Alopecia; Frontal Fibrosing Alopecia (FFA), Folliculotropic Mycosis Fungoides (FMF), Lichen Planus (LP).