Recurrent primary intracranial myxofibrosarcoma: a case report and review of the literature.

Primary intracranial myxofibrosarcoma (MFS) is an exceedingly rare mesenchymal malignancy, with only a few cases reported. We report a 34-year-old male with a right frontal lobe MFS who subsequently developed two non-contiguous recurrences in the right temporal and left frontal lobes. Histopathological examination revealed a stepwise progression from low- to intermediate- to high-grade disease, accompanied by progressively increasing Ki-67 labeling indices. Notably, the pattern of spatially separate recurrences suggests the possibility of cerebrospinal fluid-mediated dissemination. This case highlights the aggressive and heterogeneous nature of intracranial MFS and underscores the importance of long-term, comprehensive follow-up to detect recurrences, particularly at non-contiguous sites.