The Neurosurgical Challenge of Primary Central Nervous System Lymphoma Diagnosis: A Multimodal Intraoperative Imaging Approach to Overcome Frameless Neuronavigated Biopsy Sampling Errors

Abstract

Background: Intracranial lymphoma remains a challenging differential diagnosis in daily neurosurgical practice. We analyzed our early experience with a surgical series of frameless neuronavigated biopsies in Primary CNS Lymphomas (PCNSLs), highlighting the importance of using an intraoperative combined imaging protocol (5-ALA fluorescence, i-CT and 11C-MET-PET) to overcome potential targeting errors secondary to tumor volume reduction after corticosteroid therapy. Materials and methods: All patients treated for PCNLSs at our center in a 24-month period (1/1/2019 to 31/12/2020) were analyzed. Our cohort included 6 patients (4 males), with a median age of 67 years (59–82). A total of 45 samples were evaluated for correlation between intraoperative fluorescence and pathological findings. 39 samples biopsy were evaluated. Results: 54% samples showed a clear diagnosis of PCNSL. 64% of samples had a lava like fluorescence. i-CT scan showed tumor volume changes, in comparison to preoperative MRI, in all cases and helped in planning correct trajectories on updated imaging; after biopsy i-CT confirmed sampling accuracy and excluded procedural complications in all cases. Conclusions: We believe that the use of a multimodal intraoperative imaging approach overcomes the demonstrated PCNSL morphological changes caused by corticosteroid therapy and gives a reliable tissue diagnosis by frameless biopsy.