Polymorphous Low Grade Neuroepithelial Tumor of the Young

**Semantic type:** Neoplastic Process

**Definition:** A low-grade cerebral tumor associated with seizures and in many cases refractory epilepsy. It usually occurs in the second and third decades of life. It is characterized by the presence of oligodendroglioma-like components. It may also contain astrocytic components. MAPK pathway-activating genetic alterations play a role in the development of this tumor. Causative gene alterations include mutations resulting in the expression of BRAF p.V600E and gene fusions involving FGFR2 or FGFR3 genes. IDH gene mutations and 1p/19q codeletion are not present.

**Synonyms:** - Diffuse or Nonspecific Form of Dysembryoplastic Neuroepithelial Tumor - Long-Term Epilepsy-Associated Tumor - Massively Calcified Low Grade Glioma - Massively Calcified Low-Grade Glioma - PLNTY - Polymorphous Low-Grade Neuroepithelial Tumor of the Young