SURG-03. Durability of an Early Management Strategy Facilitating Endoscopic Removal of Recurrent Choroid Plexus Carcinoma

BACKGROUND: Choroid plexus carcinoma (CPC) is a rare, primarily intraventricular neoplasm with a dismal prognosis. Extent of surgical removal is correlated with improved outcomes but is frequently limited due to tumor vascularity and size. Information related to surgical management and molecular drivers of tumor recurrence is currently limited. Here we characterize a case of multiply recurrent CPC treated solely with sequential endoscopic tumor removals over a 10-year period and highlight its genomic properties. METHODS: We performed a retrospective review of a 16-year-old female treated for CPC with local and distal recurrences undergoing repeat excision with minimally invasive neuro-endoscopy. We describe technical nuances associated with neuro-endoscopic intervention, mean hospital stay, complications, and perioperative MRI. Whole exome sequencing (WES), targeted sequencing, and methylation profiling results over time are reviewed. RESULTS: Five years after standard treatment, the patient was evaluated for a distant intraventricular recurrence. A total endoscopic resection was performed given the local, non-disseminated recurrence pattern. WES results included NF1, PER1, and GLI3 mutations as well as FGFR3 gain, and was negative for TP53 alterations. Repeat sequencing on a recurrence 4 years later showed persistent NF1 and FGFR3 alterations. Methylation profiling was consistent with “plexus tumor, subclass pediatric B”. Overall, short-term surveillance neuroimaging detected four isolated recurrences, all treated with complete endoscopic resections at 5 years, 6.5 years, 9 years, and 10 years after initial CPC diagnosis. Mean hospital stay for all recurrences was 1 day with no complications from treatment. CONCLUSION: We describe a patient with 4 isolated recurrences of CPC over a decade, each treated with complete endoscopic removal, and identify an unusual set of molecular alterations that persisted over time. These outcomes support a strategy encompassing frequent neuroimaging surveillance to facilitate a minimally invasive endoscopic surgical approach at early detection and relatively low tumor mutagenicity.