Brain Metastasis in a Young Patient: Consider the Rectum.

Approximately 20% of patients with newly diagnosed colorectal cancer present with distant metastatic disease. Brain metastasis from colorectal cancer is uncommon and usually associated with metachronous metastases in other organs. We describe a rare case of a 49-year-old patient presenting with headaches and left-sided weakness found to have a solitary brain metastasis from primary rectal cancer. Primary rectal cancer, young age, lung and liver metastases, and KRAS mutation are risk factors associated with brain metastases in patients with colorectal cancer. Intracranial imaging should be considered as part of the workup in the staging of colorectal cancer in patients who are at high risk of brain metastasis.