Clinical Features, Histological Characteristics, and Disease Outcomes of Mycosis Fungoides in Children and Adolescents: A Nationwide Multicentre Cohort of 46 Patients

Background: Our objective was to describe the clinical, histological characteristics, and disease outcome of a cohort of mycosis fungoides (MF) diagnosed during childhood including disease status at adulthood. Methods: This is a retrospective multicentre survey of patients aged under 18 years at diagnosis with histologically confirmed MF. Patients' clinical and histological characteristics, treatments, and disease outcome (for patients followed for more than 12 months) were analysed. Results: Forty-six patients were included (median age at diagnosis: 11 years; M:F sex ratio: 3:1) with 39 (85%) followed for at least 12 months. Thirty-nine patients (85%) had stage I MF. Hypopigmented patches were observed in 48% and folliculotropism in 43% patients. Immunophenotype of the skin infiltrate was predominantly CD8+ in 17% of patients. Initial management included a wait-and-see strategy in 6/39 (15%), skin-directed treatment in 27 (69%), and systemic treatment in 6 (15%) patients, respectively, with partial or complete clinical response (PR or CR) observed in 28 patients (72%). 14/39 patients (36%) relapsed after initial response. After a median follow-up period of 54 months, disease status at last news was PR or CR in 31/39 (79%), stable disease in 6 (15%), and progression in 2 (5%) patients. Histological transformation was observed in 3/39 (8%). Of the 15 patients followed until adulthood, 13 (87%) had persistent MF. Discussion: This survey confirms the high frequency of hypopigmented and folliculotropic lesions and of CD8+ immunophenotype compared to adult MF patients. The long-term course is usually indolent but transformation may occur sometimes long after disease onset and the disease may persist during adulthood.

Automated summary

This study retrospectively analyzed the clinical, histological characteristics, and disease outcome of childhood mycosis fungoides (MF) patients. The results showed that most patients were in stage I MF with a high frequency of hypopigmented and folliculotropic lesions, and a significant presence of CD8+ immunophenotype. Treatment options included wait-and-see, skin-directed, and systemic treatments, with a good clinical response observed in the majority of patients, although some experienced relapse after initial response. The long-term prognosis was generally indolent, but a small portion of patients may have persistent MF into adulthood.