Clinical characteristics and treatment strategies of brainstem lesion in children with neurofibromatosis type 1.

OBJECTIVE: To investigate the clinical characteristics, treatment strategies, and prognosis of Brainstem Lesion (BSL) in children with neurofibromatosis type 1 (NF1). METHODS: A retrospective analysis was conducted on the clinical data of 269 children with NF1 admitted to Children's Hospital of Soochow University from July 2016 to March 2025. All children underwent cranial magnetic resonance imaging (MRI), and BSL was diagnosed based on imaging findings. The incidence, clinical characteristics, disease progression, and prognosis of NF1-associated BSL were analyzed. Family trio whole exome sequencing was performed in 7 of 11 children with NF1-associated BSL to explore the correlation between NF1 genotype and clinical phenotype. RESULTS: Among 269 children with NF1, 11 (4.1%) had concurrent BSL. Lesion distribution: 1 case involved the medulla and cervical spinal cord, 1 case involved the medulla, 2 cases involved the pons, 2 cases involved the tectum of the midbrain, and 5 cases involved the medulla and pons. One child with tectal lesion underwent endoscopic third ventriculostomy for obstructive hydrocephalus; at the last follow-up, the lesion size remained stable and symptoms related to hydrocephalus improved. The remaining 10 cases were managed with clinical follow-up and observation; during follow-up, all clinical symptoms remained stable, with 2 cases showing radiological lesion regression and 8 cases showing stable lesion size. Family trio whole exome sequencing results of 7 children revealed NF1 gene mutations located in: exon 54, exon 16, exon 18, exon 22, exon 4, and splicing site mutations in intron 29 and intron 32 in 2 cases, respectively. CONCLUSION: The incidence of BSL in children with NF1 is comparable to international reports, with the medulla and pons being the most commonly affected sites. NF1-associated BSL mostly demonstrates biological indolence; the vast majority do not require active intervention and have a favorable prognosis. The correlation between NF1 genotype and the clinical phenotype of BSL warrants further investigation.