A Case Report on Juvenile Folliculotropic Mycosis Fungoides: A Misleading Disease.

Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma, usually affecting elderly patients. Folliculotropic mycosis fungoides (FMF) is a subtype of MF that affects the hair follicles. While it is the most common variant in adults, it is rarely described in the pediatric population. The clinical manifestations of FMF can mimic common childhood dermatoses, like atopic dermatitis (AD), which often leads to a delay in diagnosis. In the pediatric population, FMF is usually diagnosed at an early stage, and its course is often indolent. There are no guidelines for pediatric FMF; treatment is generally based on the approach used in adults and responds well to phototherapy combining narrow band ultraviolet B (NbUVB) and UVA. We report the case of an 11-year-old child who was treated for several years for atopic dermatitis with follicular involvement, revealing an FMF. This case highlights the value of clinicians' persistence in diagnosing and managing such a rare condition, as well as the essential role of the dermoscopic tool in identifying patterns that may improve the early diagnosis of MF.