Pilomyxoid astrocytoma, an entity described as a histological variantof pilocytic astrocytoma, is a rare primary tumor of the centralnervous system. It is usually located in the hypothalamic-chiasmaticarea, affecting children with a mean age of 10 months. It has ahigh rate of recurrence and cerebrospinal fluid dissemination,which may be present throughout the neuroaxis. Due to itstopography, it may present developmental delay in childhood anddiencephalic syndrome, characterized by extreme weight loss, lackof fat accumulation, hyperactivity, euphoria and alertness. Magneticresonance imaging has an important role in its diagnosis, stagingand follow-up of pilomyxoid astrocytoma. However, for a definitivediagnosis, anatomopathology is particularly important to differentiateit from pilocytic astrocytoma. Some cases, as in this present one,have simultaneous histological features of pilocytic and pilomyxoidastrocytomas, constituting a group called intermediate pilomyxoidastrocytoma. Surgery is the best treatment option and it usuallyrequires adjuvant therapy.