Molecular heterogeneity of pediatric choroid plexus carcinomas determines the distinctions in clinical course and prognosis.

BACKGROUND: Choroid plexus carcinomas (CPCs) are rare aggressive pediatric tumors of the brain with no treatment standards. Genetic profiling of CPCs is often confined to possible association with Li-Fraumeni syndrome, though only about a half of CPCs develop from syndromic predispositions. Whole-chromosome gains and losses typical of CPCs reflect genomic instability of these tumors, but only partially explain the aggressive clinical course. METHODS: This retrospective study enrolled 25 pediatric patients with CPC, receiving treatment between January 2009 and June 2022. Molecular-genetic testing was performed for 20 cases with available tumor tissue and encompassed mutational status, chromosomal aberrations, and gene expression profiles. We analyzed several factors presumably influencing the outcomes, including molecular profiles and clinical parameters. The median follow-up constituted 5.2 years (absolute range 2.8-12.6 years). RESULTS: All studied CPCs had smooth mutational profiles with the only recurrent event being TP53 variants, either germline or somatic, encountered in 13 cases. Unbalanced whole-chromosome aberrations, notably multiple monosomies, were highly typical. In 7 tumors, chromosome losses were combined with complex genomic rearrangements: segmental gains and losses or signs of chromothripsis. This phenomenon was associated with extremely low 5-year survival: 20.0 ± 17.9% vs 85.7 ± 13.2%; P = .009. Transcriptomically, the cohort split into 2 polar clusters Ped_CPC1 and Ped_CPC2 differing by survival: 31.3 ± 17.8% vs 100%; P = .012. CONCLUSION: CPCs split into at least 2 molecular subtypes distinguished both genomically and transcriptomically. Clusterization of the tumors into Ped_CPC1 and Ped_CPC2 significantly correlates with survival. The distinction may prove relevant in clinical trials for dedicated and patient-oriented optimization of clinical protocols for these rare tumors.

Case report: First case of undifferentiated embryonal sarcoma of the liver in a child with neurofibromatosis type 1, treated by hepatic chemoperfusion with transcatheter arterial chemoembolization.

Introduction: In this report we firstly describe undifferentiated embryonal sarcoma of the liver (UESL) in a patient with neurofibromatosis type 1 (NF1), fatally complicated by synchronous malignant peripheral nerve sheath tumor (MPNST) with a highly aggressive metastatic course. The case also represents our first experience of chemoperfusion involving the transcatheter arterial chemoembolization (TACE) in a pediatric patient, applied as a treatment for UESL. Case presentation: A 13-year-old girl was diagnosed with NF1 and presented with a liver tumor identified as UESL by histological assessment. The tumor was refractive to the conventional first-line chemotherapy. The patient received hepatic chemoperfusion with TACE, which was efficacious; however, the overall curative outcome was unsatisfactory due to synchronous unresectable retroperitoneal MPNST with mesenteric metastases and ultimate progression of the UESL. Conclusion: This is the first reported case of UESL in a patient with NF1. The results demonstrate the efficacy of hepatic chemoperfusion with TACE in pediatric UESL.