Pilomyxoid astrocytoma in the adult cerebellum

• Pilomyxoid astrocytoma was previously considered a pilocytic astrocytoma subtype.
• However, pilomyxoid astrocytoma has distinct histology and prognosis.
• Pilomyxoid astrocytoma in adults is uncommon with only 21 reported cases.
• Cerebellar location of pilomyxoid astrocytoma in children and adults is unusual.
• We report the first case of cerebellar pilomyxoid astrocytoma in an adult female.

Pilomyxoid astrocytoma (PMA) is a recently recognised World Health Organization (WHO) Grade II tumour that was previously characterised as a subtype of the WHO Grade I pilocytic astrocytoma (PA). PMA has a histological appearance distinct from PA and a poorer prognosis due to its greater propensity for local recurrence and cerebrospinal dissemination. Although originally considered a paediatric tumour involving mainly the hypothalamic and chiasmatic region, reports of the lesion occurring in the adult population and other areas of the neuroaxis are emerging. We review the literature on PMA within the adult population and present the first case of PMA in the cerebellum of an adult female.