Leptomeningeal metastasis from colorectal cancer treated with folinic acid, fluorouracil, and oxaliplatin chemotherapy plus bevacizumab: A case report.

Leptomeningeal metastasis (LM) from colorectal cancer is rare. LM is characterized by rapid progression, making diagnosis and treatment challenging, and are associated with a poor prognosis. A 63-year-old man undergoing chemotherapy with bevacizumab for colorectal cancer was admitted to our hospital with loss of appetite. On admission, he experienced frequent episodes of loss of consciousness. Imaging to identify the underlying cause revealed no abnormalities. Cytological examination of cerebrospinal fluid confirmed LM. Because of worsening symptoms, the patient had difficulty communicating, thus preventing continuation of chemotherapy. He died at 3 weeks post-admission. In patients with cancer who exhibit central nervous system symptoms without abnormal imaging findings, LM should be considered even if the primary tumor is in the transverse colon. In such cases, cytological examination of cerebrospinal fluid and imaging studies should be conducted. This rare case of LM from colorectal cancer after resection and chemotherapy with molecularly targeted agents yielded insights that might guide future treatment strategies.