PO83DESMOPLASTIC NON-INFANTILE GANGLIOGLIOMA - A RARE CASE OF MALIGNANT TRANSFORMATION AND A REVIEW OF THE LITERATURE

Abstract

INTRODUCTION: Desmoplastic infantile gangliogliomas (DIG) are rare, supratentorial glioneuronal tumours of infants. They are histologically benign and considered as WHO grade I tumours. When presenting in children over the age of 1, they are termed desmoplastic non-infantile ganglioglioma (DNIG) and are more rare. They are not usually associated with malignant behaviour. We present a rare case of recurrent DNIG with malignant transformation. METHOD: A four year-old girl presented with a four-month history of worsening headaches, aggressive behaviour and left facial droop. MRI revealed a large right parieto-occipital lesion with mass effect. The lesion was subtotally resected. Histology was consistent with desmoplastic infantile ganglioglioma, WHO Grade I. Follow up MRIs demonstrated aggressive growth requiring further debulking in 7 months and 10 months. The subsequent biopsies showed similar features; however increasing mitotic activity in the predominant desmin positive astrocytic cells. The proliferation index (Ki67) was focally up to 4% in the first biopsy; increasing to 8% and 12% in the subsequent biopsies. Histology from the third resection was consistent with anaplastic ganglioglioma, WHO Grade III. CONCLUSION: This case of DNIG demonstrated aggressive growth despite multiple operative interventions, and histology strongly suggesting malignant transformation. Histology has shown malignant transformation, which has only been reported in a handful of cases in the literature. This has important implication for the follow up and management of these lesions.