False-positive inflammatory change mimicking glioblastoma multiforme under 5-aminolevulinic acid-guided surgery: A case report

BACKGROUND: 5-aminolevulinic acid (5-ALA)–guided surgery is one of the gold standard perioperative modalities for maximum resection of malignant gliomas. However, it should be noted that 5-ALA fluorescence does not definitively indicate the presence of malignant tumor cells. CASE DESCRIPTION: We report a rare case of false-positive lesion mimicking glioblastoma multiforme (GBM) under 5-ALA-guided surgery. A 44-year-old woman presented with persistent headache and flickering in her eyes. Magnetic resonance imaging showed enhanced lesion with perifocal edema in the left occipital lobe. We performed 5-ALA-guided surgery for the lesion, during which strong fluorescence was observed, but evaluation of the intraoperative frozen section revealed only inflammatory cells. We concluded the tumor resection once adequate decompression had been achieved, and made the final pathological diagnosis of inflammatory change following an unknown infection. CONCLUSION: Neurosurgeons should be aware of false-positive lesions mimicking GBM under 5-ALA guided surgery.