Genomic Diversity and Clinical Variability in Pediatric Primary Cutaneous Anaplastic Large Cell Lymphoma: A Case Series.

Primary cutaneous anaplastic large cell lymphoma (pcALCL) is a rare pediatric CD30-positive T-cell lymphoproliferative disorder with an excellent prognosis, but its genomic drivers are poorly defined. We report three children with skin-limited disease demonstrating striking molecular heterogeneity, including NPM::ALK, NUP214::FRK, and a novel PICALM::JAK2 fusion not previously described in pcALCL. Clinical courses ranged from spontaneous regression to systemic therapy, yet all achieved durable complete remission without progression over 31-50 months. These findings highlight previously unrecognized genomic diversity and expand the molecular landscape of pediatric pcALCL.