Abstract
BACKGROUND: Multicentric glioblastoma is a rare and aggressive brain tumor involving multiple, noncontiguous lesions. Its prognosis is generally poor due to the tumor's invasive nature and the challenges associated with achieving complete resection. Although contrast-enhanced MRI is currently the gold standard for diagnosis, it has limitations in visualizing the full extent of tumor infiltration. Recent studies have suggested that positron emission tomography (PET) using 18F-fluciclovine is superior to MRI in detecting tumor spread beyond the contrast-enhanced areas and potentially contributes to the diagnosis and management of glioblastoma. OBSERVATIONS: Here, the authors report the case of a patient with a small distant lesion detected by 18F-fluciclovine PET but not by contrast-enhanced MRI. A 62-year-old man presented with aphasia and apraxia. Initial gadolinium-enhanced MRI revealed a multilobular tumor in the left parietal lobe. At the same time, 18F-fluciclovine PET was performed and revealed an additional small lesion in the right cingulate gyrus, which was not visible on the initial MRI. Considering tumor multicentricity, the patient underwent stereotactic biopsy, which confirmed glioblastoma. LESSONS: 18F-fluciclovine PET can be a valuable tool for detecting distant lesions, early diagnosis, and surgical and radiation planning in multicentric glioblastoma. https://thejns.org/doi/10.3171/CASE25398.