Fibrillary Astrocytoma

**Semantic type:** Neoplastic Process

**Definition:** The most frequent histological variant of diffuse astrocytoma. It is predominantly composed of fibrillary neoplastic astrocytes. Nuclear atypia is a diagnostic criterion but mitotic activity, necrosis and microvascular proliferation are absent. The occasional or regional occurrence of gemistocytic neoplastic cells is compatible with the diagnosis of fibrillary astrocytoma. (WHO)

**Synonyms:** - Fibrillary astrocytoma - Fibrillary astrocytoma - Fibrous astrocytoma