ABSTRACT
BACKGROUND: Mycosis fungoides (MF) is predominantly a disease of older patients, but occasionally occurs in children. The aims of the current study were to describe the clinical presentation, pathologic features, and disease progression (DP) in patients who developed MF before age 16 years. METHODS: A retrospective study was performed. Patients with juvenile-onset MF were identified from our databases. Clinical features were determined from the medical records and patient interviews. Histologic, immunohistochemical, and T-cell receptor (TCR) gene analysis was performed. RESULTS: Thirty-four patients were identified: 50% had Stage IA disease, 47% had Stage IB disease, and 3% had Stage IIA disease. The male-to-female ratio was 2:1. Clinical features included hypopigmented lesions (24%), poikiloderma (26%), pilotropic disease (9%), and disease associated with lymphomatoid papulosis (18%). Twenty-eight patients had diagnostic histology, and six patients were included on the basis of compatible histology and a TCR clone in lesional skin. A cytotoxic immunophenotype was observed in 38%, including 71% of patients with hypopigmented lesions. Overall disease-specific survival (DSS) rates at 5 and 10 years were 95% and 93%, respectively. DP rates were 5% at 5 years and 29% at 10 years. Subgroup analysis demonstrated improved DSS and reduced DP in patients with Stage IA disease, those with hypopigmented or poikilodermatous lesions, and those with associated lymphomatoid papulosis. CONCLUSIONS: The prognosis for juvenile-onset MF is similar to that of adult-onset disease. There was an overrepresentation of a cytotoxic phenotype, which was most marked in hypopigmented variants. Widespread cutaneous disease (Stage IB) indicated a less favorable outcome.
