RARE-37. SURGICAL MANAGEMENT OF INCIDENTAL DIFFUSELY INFILTRATING GLIOMAS: A SINGLE INSTITUTIONAL EXPERIENCE

Abstract

INTRODUCTION: Uncommonly, diffusely infiltrating gliomas (DIGs) are identified incidentally while asymptomatic. Early surgical management of these tumors has been suggested to improve outcome. We set out to identify and review the characteristics and outcomes of patients with incidental, asymptomatic DIGs. METHODS: All DIGs surgically treated by the lead author between 2012 and 2016 were analyzed in order to identify cases that were discovered incidentally. Patients with incidentally discovered were identified and retrospectively reviewed. “Incidental” was defined as a finding on imaging that was obtained for a reason not attributable to the glioma, such as trauma, headache or neurological symptoms not attributable to the lesion. RESULTS: 327 patients between the ages of 19-83 underwent surgery for DIGs. Eleven (4m, 7f) patients (11/367 3.00%) were identified that harboured incidental gliomas. The most common reasons for head imaging were imaging performed to evaluate symptoms attributable to a different problem (4, 36.4%), imaging screening for other diagnoses (4, 36.4%) and trauma (3, 25%). Pathology of these lesions (based on WHO 2007 criteria) included Astrocytoma GrII (n=3), Oligodendroglioma GrII (n=4), Oligoastrocytoma GrII (n=2), and Glioblastoma (n=2). Eight tumors (8/11, 72.7%) harboured IDH1 (R132H) mutations. Two patients underwent biopsies only due to large size and extensive infiltration of the tumors, the 9 remaining patients underwent surgical resection of their tumors. No patients in this small cohort experienced post-operative complications. CONCLUSION: This retrospective cohort of incidentally discovered surgically managed DIGs demonstrates that the majority of lesions are IDH mutated and low grade. Incidentally discovered lesions are usually of small size and can be managed with low surgical risk. Ongoing follow-up will be required in order to determine progression-free and overall survival in this group of patients.