Folliculotropic Mycosis Fungoides: Update on Diagnosis, Clinicopathological Stage, and Management

Folliculotropic mycosis fungoides (FMF) is a rare subtype of MF, characterized by prominent folliculotropism in histopathology. Clinically, FMF exhibits polymorphic presentations, mainly including follicular papules, plaques, alopecia, and other nonspecific lesions, with a predilection for the head and neck region, leading to frequent misdiagnosis. Historically, FMF was perceived as an aggressive subtype with an unfavorable prognosis, often regarded as advanced‐stage MF requiring aggressive combination therapies. However, recent studies have identified a subset of FMF with indolent progression and favorable prognosis, which can achieve remission through skin‐directed therapies (SDTs). Therefore, FMF treatment strategies should follow the stage‐adapted principles such as classical MF, with individualized regimens based on disease staging. This review comprehensively elaborates the diagnostic criteria and clinicopathological staging system of FMF, with a focus on stage‐based therapeutic principles, aiming to guide clinical practice.