Identification of BAP1 Germline Mutation in a Pediatric Patient With Skull Base Meningioma.

Genetic testing based on family history and tumor type may miss numerous germline mutations. This case report describes an adolescent girl with a rare skull-base meningioma. Initial imaging suggested schwannoma but germline genetic testing with schwannomatosis panel (NF2, LZTR1, and SMARCB1) was negative. A stepwise surgical approach prioritized facial nerve preservation, followed by tumor removal. Histopathology identified the tumor as a meningothelial meningioma, WHO grade 1, rather than the initially suspected schwannoma. Comprehensive tumor-normal sequencing revealed a germline splice site variant in BAP1 (c.122G+1 G>T) and a tier 2 somatic variant in PBMR1 (c.3263_3269delinsA). This case highlights the value of combined somatic and germline genomic evaluations in complex diagnoses. Identifying the BAP1 mutation enabled preventive care, genetic testing for relatives, and tailored cancer screening. It underscores the need for thorough genomic assessments and multidisciplinary strategies to optimize outcomes in rare pediatric conditions.