Usefulness of intraoperative photodynamic diagnosis using 5-aminolevulinic acid for meningiomas with cranial invasion: technical case report.

OBJECTIVE We present a case of a meningioma in which photodynamic diagnosis (PDD) using 5-aminolevulinic acid was very useful in identifying the cranial involvement. CLINICAL PRESENTATION An 83-year-old woman presented with a bony, hard, immobile bulge in her left forehead. Computed tomographic scans showed a thickening in the left frontal bone with a flat mass underneath. Magnetic resonance imaging scans revealed that enhancing lesions spread to the dura mater and subcutaneous tissue around the thickened frontal bone, reaching the upper margin of the left orbit. INTERVENTION Intraoperative PDD using 5-aminolevulinic acid indicated the optimal extent of the excision by showing clear fluorescence of affected tissues. The tumor was totally resected and diagnosed as an atypical meningioma. Histopathological examination confirmed the consistency of the extent of tumor invasion with affected lesions on PDD. CONCLUSION To the best of our knowledge, this is the first case demonstrating the efficacy of PDD using 5-aminolevulinic acid for a meningioma with cranial invasion. Additional studies are warranted, as shown in cases of malignant gliomas.