Pilomyxoid astrocytomas are type of tumors rarely seen in the central nervous system as a variant of pilocytic astrocytoma. They are often localized in hypothalamic-chiasmatic area and seen in early childhood. They exhibit different histological characteristics and more aggressive behaviors compared to pilocytic astrocytomas. Although cases with malignant transformation were reported in pilocytic astrocytomas, no pilomyxoid astrocytoma patients was reported with malignant transformation. We have presented a pilomyxoid astrocytoma patient, since it is rarely seen in adulthood and shows malignant transformation histopathologically.