Diagnostic Value of Cerebrospinal Fluid Level of Carcinoembryonic Antigen in Patients with Leptomeningeal Carcinomatous Metastasis

BACKGROUND AND PURPOSE Multifocal seeding of the leptomeninges by malignant cells, which is usually referred to as leptomeningeal carcinomatous metastasis, produces substantial morbidity and mortality. The diagnosis of leptomeningeal metastasis is usually established by cerebrospinal fluid (CSF) investigation, including cytology, cell counts, protein, glucose, and a tumor marker such as carcinoembryonic antigen (CEA). This study examined the diagnostic value of CEA in the CSF. METHODS We measured the CSF CEA level in 32 patients with leptomeningeal metastasis. The control group consisted of 19 cancer patients without leptomeningeal metastasis. CEA was measured by the chemiluminescent emission method. RESULTS The CEA level was significantly higher in patients with leptomeningeal metastasis than in the control group (p<0.005). The level of CSF protein was higher and that of CSF glucose was lower in patients with leptomeningeal metastasis than in the control group (p<0.005). CONCLUSIONS The CSF CEA level is useful for diagnosing leptomeningeal carcinomatous metastasis. The CSF levels of protein and glucose are also useful in the diagnosis.