Rosette-forming glioneuronal tumour (RGNT) of the fourth ventricle: a highly aggressive case.

Background: The rosette-forming glioneuronal tumour (RGNT) is a rarely encountered tumour that has been included as a new entity in the 2007 edition of the "World Health Organization (WHO) Classification of Tumours of the Central Nervous System". We describe a rather unusual case of multifocal cerebellar RGNT, located in the spinal cord and displaying leptomeningeal spread.
Clinical Presentation: Twenty-four-year-old male with history of long-lasting headaches. A magnetic resonance scan revealed three heterogeneous lesions located within both cerebellar hemispheres and the left cerebellopontine angle, in addition to a spinal cord lesion at the level of the cervical region, and images of leptomeningeal spread. Interventions were performed in two stages; these involved resection of two cerebellar lesions, with a histopathological diagnosis of RGNT with atypical microvascular proliferation and focal necrosis. Although these tumours appear to be benign, our case debuted in an aggressive form, both from the radiological point of view and with respect to its histopathological characteristics. For this reason, the patient received adjuvant therapy with chemotherapy and radiotherapy.
Conclusions: Experience of RGNT is limited. The prognostic significance of the histological findings of vascular proliferation and necrosis is still unknown. The clinical improvement in our patient endorses our decision to perform aggressive treatment.