18F-Fluciclovine PET enables accurate and safe resection of malignant brain tumors: illustrative cases.

backgroundIn malignant brain tumor surgery, maximal safe resection is essential to lower recurrence while minimizing complications. However, accurate preoperative assessment of tumor infiltration remains difficult and an unmet need. 18F-Fluciclovine (18F-FACBC) PET, an innovative molecular imaging technique, has recently emerged as a preoperative tool. The authors present cases highlighting its clinical utility. OBSERVATIONS: The authors report on the cases of 3 brain tumor patients: a 54-year-old female with glioblastoma, a 17-year-old male with recurrent teratoma, and a 24-year-old female with inflammatory myofibroblastic tumor. In all cases, preoperative 18F-FACBC PET was performed, gross-total resection was achieved, and no patient developed permanent neurological deficits. In a representative case, 18F-FACBC identified a tumor-infiltrated region not visualized on contrast-enhanced MRI and indistinguishable from normal brain during surgery; this region was resected and later histopathologically confirmed as tumor tissue. Without PET, it would likely have remained unresected. Surprisingly, molecular analysis suggested that 18F-FACBC accumulated mainly not in tumor cells but in infiltrating immune cells, contributing to the imaging signal. LESSONS: 18F-FACBC PET can aid in the accurate resection of malignant brain tumors and improve outcomes. Yet, the mechanisms of uptake and visualization remain unclear. Larger cohort studies are needed to confirm the long-term efficacy of this promising imaging tool. https://thejns.org/doi/10.3171/CASE25707.