Juvenile mycosis fungoides: cutaneous T-cell lymphoma with frequent follicular involvement.

BACKGROUND: The literature on mycosis fungoides (MF) in children/adolescents is sparse. OBJECTIVE: We sought to evaluate the characteristics of juvenile MF in a large cohort. METHODS: Data were collected on all patients with MF, aged 18 years or younger at the time of clinicopathologic diagnosis, who attended the Rabin Medical Center Dermatology Department, Petach Tikva, Israel, between 1994 and 2012 and were followed up prospectively. RESULTS: There were 50 patients (30 male; mean age 11.4 years at diagnosis); 18 (36%) had Fitzpatrick skin type IV or higher. All were given a diagnosis of early-stage disease (IA-IIA) except 1 (tumor stage, IIB). Eight had classic MF lesions only and 42 had other variants, alone or in combination; these were mainly hypopigmented MF (n = 29) and cases with subtle but clear clinicopathologic features of folliculotropic MF (FMF) (n = 18). Among the various skin-targeted therapies, psoralen plus ultraviolet A (systemic/bath) proved beneficial for FMF. During a follow-up period of 0.25 to 15 years (mean 4.5), 2 patients progressed from stage IA to IB or IIA. LIMITATIONS: Relatively short follow-up is a limitation. CONCLUSIONS: This case series shows that FMF is not uncommon in children and adolescents. It is characterized by more superficial clinical features and less heavy perifollicular lymphocytic infiltrates than adult FMF, and responds well to psoralen plus ultraviolet A. The prognosis of childhood FMF remains unclear.