Mycosis Fungoides in Pediatric Patients: A Real-Life Retrospective Study in Cuba

Mariuska Forteza Saez, Yolainy Romero Rodriguez, Maria del Carmen Llantá Abreu, Dayne Clarivel Quintero Vazquez.

Abstract

Background: Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma and accounts for fewer than 5% of cases in the pediatric population. No studies on Cuban children had previously been identified. We report the first real-life retrospective series of pediatric MF from a national oncology reference center in Cuba.

Procedure: Retrospective analysis of all patients under 18 years of age with histopathologically confirmed MF treated at the Institute of Oncology and Radiobiology (INOR), Havana, Cuba (2015–2025). Predictors of complete remission and relapse were identified by multivariable logistic regression. Time-to-event outcomes were analyzed using the Kaplan-Meier method with log-rank testing.

Results: Eighty-nine patients were included (mean age at diagnosis: 9 years). The hypopigmented variant predominated (70.8%). Early clinical stages (IA/IB) were present in 59.6%. Recombinant alpha-interferon combined with phototherapy was prescribed in 92.1% of patients. Complete remission (CR) was achieved in 100% of patients; sustained CR was documented in 34.8% at a median time to CR of 22 months (P25–P75: 12–48). Greater body surface area involvement and longer disease duration were independently and inversely associated with sustained CR. Relapse-free survival at 24 months was 84.3% (95% CI: 76.1–92.5%; 14 events); non-hypopigmented variant and darker skin phototype were independent predictors of relapse. The median institutional diagnosis delay was 3 months (range: 0.8–10.7) with no significant impact on CR. Overall survival was 100% at a median follow-up of 19 months, with no disease progression.

Conclusions: This is the first Cuban pediatric MF cohort. Interferon plus phototherapy achieves universal CR with a favorable relapse-free survival profile. The hypopigmented phenotype is dominant and confers a lower relapse risk. Early diagnosis and treatment initiation are critical for optimal sustained remission.