STMO-08 Validation of the endoscopic 5-ALA fluorescence diagnosis for intraventricular tumors

Intraoperative 5-ALA fluorescence diagnosis (PDD) has been shown to improve tumor resection rates in surgery for malignant glioma. Recently, the usefulness of PDD has been reported in tumors other than malignant glioma. However, the fluorescence of intraventricular tumors is not easy to observe under the microscope, because excitation light could not reach enough to the deepest part of the brain. Therefore, we performed endoscopic 5-ALA fluorescence diagnosis of intraventricular tumors and evaluated its usefulness. Ten cases of intraventricular tumors were included in the study. There were 3 germ cell tumors, 2 metastatic brain tumors, 2 pilocytic astrocytomas, 1 malignant lymphoma, 1 subependymoma, and 1 medulloblastoma (recurrent). The tumors were located in the third ventricle in four cases, the lateral ventricle in three cases, the lateral ventricle and the third ventricle in two cases, and the aqueduct in one case. Tumor removal was performed in 6 cases and tumor biopsy in 4 cases. Intraoperative fluorescence could be observed in eight cases: three germ cell tumors, two metastatic brain tumors, two pilocytic astrocytomas, and one malignant lymphoma. Subependymoma and medulloblastoma did not show fluorescence. Among the cases with confirmed fluorescence, the fluorescent sites were targeted for biopsies for germ cell tumors and malignant lymphomas. For metastatic brain tumors and pilocytic astrocytomas, the extent of removal was determined at the time of removal, and the presence of residual tumor was confirmed by fluorescence after removal. Endoscopic 5-ALA fluorescence diagnosis for intraventricular tumors was useful in determining the target of biopsy or the extent of excision and in assessing residual tumors.