Rosette-forming glioneuronal tumor outside the fourth ventricle: a case-based update

Rosette-forming glioneuronal tumors (RGNTs) that do not involve the fourth ventricle are rare. RGNTs were originally thought to be exclusively localized into the fourth ventricle but were found in various anatomical localizations. We review the literature and found 32 cases of this particular RGNT. The outcome was excellent with no mortality reported after surgical treatment. Only two patients had received adjuvant therapy for progression. We added one case of a RGNT located in the cerebellar hemisphere. She underwent a subtotal removal with no evidence of progression after. This WHO grade I tumor with a specific biphasic histopathology is of a good oncological outcome after surgical treatment. A long follow-up is needed as recurrence or metastatic progressions exist.