Two Colorectal Cancer Cases with Carcinomatous Meningitis Diagnosed by Cerebrospinal Fluid Cytology

Abstract

Carcinomatous meningitis is rare in patients with colorectal cancer. Two cases of carcinomatous meningitis originating from colorectal cancer are reported. Case 1 involved a 76-year-old man with rectal cancer, who had undergone surgery and continued third-line treatment for liver and distant lymph node metastases. He developed consciousness disturbance, and although contrast-enhanced magnetic resonance imaging (MRI) showed no abnormal findings, cerebrospinal fluid cytology confirmed carcinomatous meningitis. He died on the 27th day of hospitalization with supportive care. Case 2 was an 80-year-old woman with colon cancer as the primary tumor, who continued first-line treatment for adrenal and multiple distant lymph node metastases. She also developed consciousness disturbance, and both contrast-enhanced MRI and cerebrospinal fluid cytology confirmed carcinomatous meningitis. Despite supportive care, capecitabine via nasogastric tube, and whole-brain radiation, she died on the 23rd day of hospitalization. Carcinomatous meningitis should be considered in the differential diagnosis when unexplained neurological symptoms such as consciousness disturbance, vomiting, and headache are present, especially in cases with poorly differentiated adenocarcinoma and advanced lymph node metastasis.