<prompt> Young child with mass in posterior cranial fossa showing mural nodule. Diagnosis isHemangiocytic pericytomaAstrocytoma PilocyticEpendymomaGBM  <response>: Pilocytic astrocytoma is a well defined glial cell tumor,presenting as a large cystic lesion with a brightly enhancing mural nodule.Calcification can be present in around one- fifth of the cases.They typically arise from the midline structures, around 60 are in cerebellum. Associations: There is a strong association with , there is predominantly a mass effect with signs of raised intracranial pressure, especially when hydrocephalus is present. Bulbar symptoms or cerebellar symptoms may also be present. Reference: GHAI Essential pediatrics, 8th edition 