Pilomyxoid astrocytoma (PMA) is a rare central nervous system tumor that has been included in the 2007 World Health Organization Classification of Tumors of the Central Nervous System. Due to its more aggressive behavior, PMA is classified as Grade II neoplasm by the World Health Organization. PMA predominantly affects the hypothalamic/chiasmatic region and occurs in children (mean age of occurrence = 10 months). We report a case of a 24-year-old man who presented with headache, nausea, and vomiting. Brain CT and MRI revealed a mass occupying only the third ventricle. We performed partial resection. Histological findings, including monophasic growth with a myxoid background, and absence of Rosenthal fibers or eosinophilic granular bodies, as well as the strong positivity for glial fibrillary acidic protein were consistent with PMA.