A 5-year-old girl with neurofibromatosis type 1 (NF1) presented with a 1-month history of progressive left hemiparesis. Brain MRI revealed a large extra-axial right frontal mass (figure 1). The pathologic findings after complete resection were compatible with malignant triton tumor (MTT) (figure 2). MTT is an aggressive subtype of malignant peripheral nerve sheath tumor, histopathologically characterized by a high-grade spindle cell tumor, with immunohistochemistry demonstrating reaction to skeletal muscle stains, such as desmin and myogenin.1,2 MTT is associated with NF1 in 38% of cases.1 Intracranial MTT is exceedingly rare, usually presenting radiologically as a rapidly enlarging, heterogeneous, and enhancing mass.2

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