Pilomyxoid astrocytoma (PMA) is a rare variant of pilocytic astrocytoma. Compared with pilocytic astrocytoma, PMA is more aggressive, has a higher rate of local recurrence, and often disseminates to the leptomeninges. Leptomeningeal gliomatosis is another rare but often intractable neoplasm. PMA presenting as leptomeningeal gliomatosis can be a therapeutic challenge, particularly in young children for whom many pediatric oncologists consider radiation therapy only as a back-up treatment. However, chemotherapy, usually considered a frontline treatment for low-grade tumors such as PMA, has little impact on leptomeningeal gliomatosis.