MEK inhibition with trametinib is a successful therapy in ganglioglioma.

Gangliogliomas are predominantly low-grade primary brain tumors comprised of neuronal and glial components that are found in both pediatric and young adult populations. In the majority of cases, surgical resection of these tumors is curative. However, tumor location in eloquent centers of the brain can make surgical intervention inappropriate. Additionally, a subset of tumors progress to anaplastic ganglioglioma which carries a poor prognosis, despite resection. Activating mutations in the MAPK pathway, such as BRAF V600E, have been identified in many of these tumors. Tumors carrying such mutations have demonstrated susceptibility to MEK inhibition therapy. However, there remains a subset of ganglioglioma that do not contain a known mutation in the MAPK pathway and thus have not been targeted with MEK inhibition therapy. Here, we present a young adult ganglioglioma patient without identified MAPK pathway activation mutations who demonstrated a significant and sustained response to MEK inhibition with trametinib.