Neurodegenerative lesion of tumefactive multiple sclerosis demonstrates the fluorescence radiation from 5-aminolevulinic acid-induced protoporphyrin IX

Tumefactive multiple sclerosis (tMS) reveals imaging findings in the central nervous system alongside extensive surrounding edematous changes. The nature and etiology of the disease are often unknown. In addition, differentiation from a primary intracranial tumor is often difficult based on imaging studies alone. Therefore, surgical resection and pathological examination are often required to obtain a definitive diagnosis. A 48-year-old woman attended the clinic complaining of headaches. A ring-shaped, contrast-enhanced lesion with perifocal edema in magnetic resonance imaging was noted in the right occipital lobe. She underwent craniotomy, and pathological examination revealed a diagnosis of tMS. Intracranial findings at the time of surgical operation showed excitatory light positivity for 5-aminolevulinic acid-induced protoporphyrin IX (PPIX). In tMS lesions, the author observed PPIX accumulation, indicative of mitochondrial dysfunction. It can be hypothesized that mitochondrial metabolic disturbance would result in inhibition of heme synthesis. The hypothesis that the decrease in adenosine triphosphate (ATP) production due to heme depletion is the underlying cause of the energy deficit is one that merits further investigation. This finding of mitochondrial dysfunction accompanied by the decrement of PPIX metabolization might be important for the etiologic analysis of tMS.