Folliculotropic Mycosis Fungoides - A Case Report

Abstract Mycosis fungoides (MF) belongs to a group of primary cutaneous T-cell lymphomas, with characteristic small- to medium-sized neoplastic T-lymphocytes with hyperchromatic and cerebriform nuclei. Folliculotropic mycosis fungoides (FMF) represents a variant of mycosis fungoides, which is histologically characterized by folliculotropic T-cell infiltrates, with or without mucinous degeneration of the hair follicles. Clinical features of FMF are characterized by appearance of grouped follicular papules, acneiform lesions, indurated plaques, sometimes tumors, which usually involve the head and neck region. The diagnosis is based on clinical presentation, histopathological and immunohistochemical (IHC) findings of skin biopsy specimens. The treatment of FMF, and generally MF, should be stage-adapted. Case report: We present a case of a 33-year-old male with an eight-month history of erythematous papules on his forehead accompanied by intense pruritus. Histopathological findings showed folliculotropic and perivascular lymphocytic infiltrates. An increased CD4/CD8 ratio of interfollicular lymphocytes with accumulation of Langerhans cell confirmed the diagnosis of FMF. Our patient was diagnosed with an early stage - IA, and P-UVA phototherapy was recommended due to ineffectiveness of prescribed topical corticosteroids that had shortterm effects. Conclusion: Folliculotropic mycosis fungoides represents a diagnostic challenge due to the great diversity of clinical manifestations. We presented a rare case of folliculotropic mycosis fungoides in a young adult, who presented with erythematous papules, accompanied by intense pruritus on the forehead, which lasted for several months. Histopathological and IHC analysis confirmed the diagnosis of folliculotropic mycosis fungoides stage IA. Due to an inadequate response to a topical corticosteroid, P-UVA phototherapy was administered, as well as close follow-up, essential for timely treatment of this frequently therapy-resistant disease.