Abstract
1423
Objectives: Most primary central nervous system lymphoma (PCNSL) tumors arise in the periventricular region, commonly in the corpus callosum, thalamus and basal ganglia. An unusual location and atypical radiologic appearance may hinder correct preoperative diagnosis and lead to a craniotomy with more complications rather than a stereotactic biopsy recommended by the guideline if the tumor was more suspected of lymphoma. The aim of this study was to explore whether brain PET/CT, 18F-FDG, 68Ga-PRGD2 or 11C-methionine (MET) could help with correct preoperative diagnosis and decide whether craniotomy versus stereotactic biopsy is performed. Methods: Our database of brain tumor patients with preoperative PET/CT was searched retrospectively by postoperative pathology diagnosis of PCNSL at unusual locations. Semi-quantitative analysis using SUVmax was performed. The surgery mode was initially chosen by three independent experienced neurosurgeons without a nuclear medicine (NM) doctor’s differential diagnosis. Then, the final decision was made by a tumor board that included NM doctors. Thus, it was determined whether differential diagnosis using PET imaging could change the surgery mode and decrease complications. Results: Overall, six patients with newly developed PCNSL at unusual locations, including in the occipital lobe, cerebellar pontine angle (CPA), etc. underwent 18F-FDG, 68Ga-PRGD2 and 11C-MET PET/CT preoperatively. The 18F-FDG SUVmax of the tumor ranged from 20.06-39.3. One patient underwent craniotomy, while stereotactic biopsy was used for the other five patients. Conclusions: Brain PET/CT imaging is a noninvasive modality that is useful in improving the accuracy of preoperative diagnosis for PCNSL at unusual locations. This technique may assist experienced neurosurgeons in making correct medical decisions with stereotactic biopsy while preventing many complications associated with craniotomy.
