LAUSR

Background: Plexiform schwannomas are usually sporadic. In hereditary diseases they are linked to benign and aggressive malignant tumors. Schwannomas of the hypoglossal nerve are very rare and mostly develop at the skull base without plexiform variant. Case presentation: In the floor of the mouth a salivary gland tumor was suspected on imaging of an 11-year-old girl. Intraoperatively the tumor was connected to the hypoglossal nerve. There were no postoperative functional deficits. Histology identified a plexiform schwannoma with collagen pseudorosettes. Molecular-genetic testing of genomic and tumor DNA could not identify a pathogenic variant in the NF2, SMARCB1, or LZTR1 genes. The patient is currently free of disease 74 months postoperatively. Conclusion: In case of a histological diagnosis of schwannoma, particularly in children, immunohistochemical examinations should be carried out and depending on these results human-genetic diagnosis is indicated.