ID #69 APC Mutations and Brain Cancer Risk
Nouha Bouayed AbdelmoulaAbstract
Introduction
Familial adenomatous polyposis (FAP), due to APC mutations, confers an almost 100% lifetime risk of colorectal cancer.
Methods
We report a family with a pathogenic APC mutation affecting the mother and three daughters, confirmed by Sanger sequencing on peripheral blood. The objective was to review the frequency and types of central nervous system (CNS) tumors associated with APC mutations and summarize current surveillance recommendations.
Results
All four individuals are at high risk of colorectal cancer and require structured colonoscopic surveillance. Rarely, FAP is associated with CNS tumors, as described in case reports including medulloblastomas, gliomas, and craniopharyngiomas. The frequency of CNS tumors in APC mutation carriers is extremely low (<1%), and most families never develop such tumors. International guidelines recognize the rare association with brain tumors and do not recommend routine CNS imaging for APC mutation carriers. Surveillance focuses on colorectal, duodenal, thyroid, and desmoid tumor risk.
Conclusions
While APC mutations carry a very small risk of CNS tumors, current evidence and guidelines do not support systematic cerebral surveillance. Early genetic testing and structured follow-up remain critical to manage the high colorectal cancer risk and other extracolonic manifestations.