5-aminolevulinic acid-guided endoscopic biopsy with violet light-emitting diode flashlight in malignant glioma: Technical note

Abstract

Background: 5-aminolevulinic acid (5-ALA) photodynamic diagnosis (PDD) has enabled better identification of malignant tumor cells and real-time intraoperative guidance. Here, we report a reasonable procedure for 5-ALA-guided endoscopic biopsy with a violet light-emitting diode (LED) flashlight for deep-seated malignant gliomas.

Methods: A 63-year-old man presented with a headache and left upper homonymous quadrantanopia. Imaging studies showed atypical lesions with non-significant and partial contrast enhancement in the right deep temporo-occipital lobe. An endoscopic biopsy was performed under the guidance of 5-ALA PDD with a violet LED flashlight.

Results: The tumor tissues, which were difficult to distinguish from normal brain parenchyma under white light, were positive for 5-ALA fluorescence. The histopathological diagnosis was astrocytoma (the World Health Organization grade 3). The patient underwent adjuvant chemoradiation therapy. Headache and anopia improved, and no recurrence was observed at 12 months follow-up.

Conclusion: This technique of neuroendoscopic biopsy guided by 5-ALA PDD fluorescence with a violet LED flashlight may allow a safe and accurate diagnosis of deep-seated malignant gliomas.

Keywords: 5-aminolevulinic acid; Endoscopic biopsy; Light-emitting diode flashlight; Malignant glioma.

Figure 1:

Instruments used for the 5-aminolevulinic acid-guided endoscopic biopsy. The white light attachment of the endoscope was removed and replaced with the violet light-emitting diode flashlight.

Figure 2:

Comparison of indicated intratumoral areas in malignant glioma: Contrast enhancement (CE) on magnetic resonance imaging, fluid-attenuated invasion recovery (FLAIR) image, conventional white light endoscopy, 5-aminolevulinic acid photodynamic diagnosis fluorescence with violet light-emitting diode flashlight, and histopathology. The tissue from inside the (1a) slight CE and (1b) hyperintense on FLAIR depicts (1c) no obvious endoscopic abnormalities, (1d) strong fluorescence, and (1e) corresponding histopathology demonstrates infiltrating anaplastic tumor cells of an astrocytoma, world health organization grade 3. The tissue from inside the (2a) non-CE and (2b) hyperintense on FLAIR shows (2c) no obvious endoscopic abnormalities, reveals (2d) vague fluorescence, and (2e) histopathologically corresponds to infiltrating anaplastic tumor cells of an astrocytoma, grade 3. The tissue from the (3a) non-CE and (3b) rim of hyperintense on FLAIR shows (3c) no obvious endoscopic abnormalities, is (3d) negative for fluorescence, and (3e) histopathologically reveals no definite infiltrating tumor cells. The subcortical tissue from the (4a) non-CE and (4b) isointense on FLAIR shows (4c) no obvious endoscopic abnormalities, is (4d) negative for fluorescence, and (4e) histopathologically reveals no definite infiltrating tumor cells. Bar = 50 µm.