P14.27 The significance of multicentric noncontrast-enhancing lesions distant from surgically resected glioblastoma: Case series of 3 patients

Abstract

Abstract BACKGROUND Glioblastoma is the most malignant primary brain tumor. The tumor location and multiplicity plays an important role in surgical and further treatment. The incidence of multiple lesions at the time of diagnosis was known as 1–20%, which showed a poor prognostic factor. Most researches has focused on multiple contrast-enhancing lesions, however, multicentric non-enhancing lesions distant from glioblastoma has been rarely evaluated. The authors reported the case series of the patient who showed multicentric non contrast-enhancing lesions without connection to histologically-proven glioblastoma. MATERIAL AND METHODS Multicentric non contrast-enhancing lesions were defined as areas of FLAIR hyperintensity and mass effect without post-contrast enhancement, separated from the histologically-proven glioblastoma in a newly diagnosed disease. Three patients who showed distant non-enhancing lesions with appearance of a multicentric low-grade glioma were included in this study. The typical enhancing lesions were surgically resected and standard chemo-radiotherapy was followed in all patients. RESULTS All patients were male and their age was 38, 60 and 65 years old respectively. Multicentric tumor location was as follows: Case 1, left frontal lobe with non-enhancing lesion in left parahippocampal gyrus; Case 2, left parietal with non-enhancing lesion in left anteromedial temporal lobe; Case 3, left thalamus with non-enhancing lesions in both basal frontal and right temporal lobe. Pathologically, the resected enhancing tumor revealed glioblastoma in 2 patients and diffuse midline glioma in 1. All tumors were IDH-wild type. The resected enhanced lesion showed no progression but all non-enhancing lesions developed contrast-enhancing tumors at 3, 13 and 17 months after initial treatment, with high tracer uptake on 18FDG-PET or 18FDOPA-PET. Despite multidisciplinary treatment, two patients died from disease progression at 30 and 32 months after diagnosis and one patient is still alive with overall survival of 15 months. CONCLUSION The appearance of multicentric non-enhancing lesions distant from a typically enhancing tumor showed an uncommon finding in glioblastoma and poor prognostic features. These lesions progress faster than expected for a low-grade glioma. These lesions should be distinguished from typical low-grade glioma and should be considered more advanced lesions than their appearances suggest.