Recurrent anaplastic transformation of a Vermian region rosette forming glioneuronal tumour - A rare entity. Case report and review of literature.

INTRODUCTION AND IMPORTANCE: Rosette forming Glioneuronal tumours (RGNT) are rare WHO grade I tumours. They have been recognised as a sole entity in the WHO classification since 2007. They are typically described as having a favourable prognosis. Since their description as a distinct entity, there have been only four reports of malignant or anaplastic transformation of RGNT. We report a case of recurrent RGNT with new anaplastic histopathological features.

CASE PRESENTATION: We present the case of a 48-year-old female who presented with a vermian region RGNT. The tumour recurred six years after initial surgical resection with new anaplastic transformation. Despite further surgery, chemotherapy, and radiation, the lesion continued to recur with high grade features.

CLINICAL DISCUSSION: RGNT is a rare variant of a mixed glial-neuronal tumour. It has been defined as a WHO grade I lesion with a favourable prognostic course. There is growing evidence that this neoplasm can demonstrate malignant transformation with aggressive behaviour.

CONCLUSION: Recurrent RGNT is a rare entity. There is a growing bank of literature surrounding this relatively new entity to aid patients and clinicians alike in management decisions. To our knowledge, we report one of only few cases of anaplastic transformation of a RGNT. A high degree of suspicion should be maintained for patients with recurrent RGNT and in suitable cases, surgical resection with adjuvant chemo-irradiation should be pursued.