Primary anaplastic pilocytic astrocytoma.

We report two adult patients with pilocytic astrocytomas with anaplastic features at initial diagnosis. Pilocytic astrocytomas are low-grade astrocytomas that occur rarely in adults. Initial presentation of a pilocytic astrocytoma with anaplastic features is particularly uncommon and making a definitive diagnosis of pilocytic astrocytoma with anaplastic features can be challenging. It is critical to differentiate glioblastoma (World Health Organization [WHO] grade 4) and pilocytic astrocytoma with anaplastic features (WHO grade 3) from pilocytic astrocytoma (WHO grade 1) as there are significant therapeutic and prognostic implications. Improved therapeutic strategies are required for pilocytic astrocytomas with anaplastic features.