We present the case of a 29 year-old male with a tumor involving the mesencephalic tectum with associated hydrocephalus. Third ventriculocisternostomy was performed along with endoscopic biopsy; this provided adequate sampling of the tumor and enabled diagnosis of rosette-forming glioneural tumor (RGNT). The patient was followed for 48 months without progression of the disease. We review the features of the previous eight cases described in the literature and discuss the advantages of a minimally invasive approach and conservative management.