Primary cutaneous lymphomas in children: a single-center retrospective analysis and narrative review of the literature.

BACKGROUND

Primary cutaneous lymphomas (PCLs) are uncommon in children, with mycosis fungoides (MF), lymphomatoid papulosis (LyP), and primary cutaneous small/medium CD4+ T-cell lymphoproliferative disorder (PCSM-TCLPD) representing the most frequent entities. Due to their rarity, available data derive mainly from case reports and small series, and diagnostic delays are frequent. This study aimed to describe the clinical, histopathological, and therapeutic features of pediatric PCLs in a single Italian referral centre and compare them with the literature evidence.

METHODS

We conducted a single-center, retrospective observational study including patients aged ≤16 years with a histologically confirmed diagnosis of PCLs, followed for at least six months at the Dermatology Unit of the University Hospital of Bologna between 2002 and 2024. Clinical, histological, therapeutic, and follow-up data were collected and analyzed.

RESULTS

Among 354 PCL patients, 10 pediatric cases were identified: six MF, three LyP, and one PCSM-TCLPD. The mean age at diagnosis was 9.1 years. MF cases were mostly early-stage (IA, 5/6), with folliculotropic (67%), hypopigmented (50%), and classic (50%) variants; all were treated with topical corticosteroids and/or PUVA, with good long-term outcomes (67% complete remission). LyP patients presented at younger ages (mean 5.7 years) with type A (N.=2) and D (N.=1) subtypes; all achieved complete remission despite recurrences, one requiring methotrexate. The single PCSM-TCLPD case was cured with surgical excision. After a mean follow-up of 8.2 years, all patients were alive, most disease-free.

CONCLUSIONS

Pediatric PCLs are rare but generally indolent, with an excellent prognosis. However, their clinical heterogeneity and diagnostic delay highlight the importance of early biopsy, integrated clinicopathological assessment, and long-term follow-up. Multicenter studies are needed to establish tailored treatment algorithms for children.