Pilocytic Astrocytoma

**Semantic type:** Neoplastic Process

**Definition:** A WHO grade 1, relatively circumscribed, slowly growing, often cystic astrocytoma occurring in children and young adults. Histologically it is characterized by a biphasic pattern with compacted bipolar cells associated with Rosenthal fibers and multipolar cells associated with microcysts and eosinophilic bodies/hyaline droplets. (WHO)

**Synonyms:** - Grade 1 Astrocytic Neoplasm - Grade 1 Astrocytic Tumor - Grade 1 Astrocytoma - Grade I Astrocytic Neoplasm - Grade I Astrocytic Tumor - Grade I Astrocytoma - Pilocytic astrocytoma - Pilocytic astrocytoma