• We described a metastatic signetring cell gastric adenocarcinoma in a 60-year-old woman who complained of progressive visual loss. The discovery of signet-ring cells in the cerebrospinal fluid established the diagnosis of mucussecreting adenocarcinoma. Histologic study of an ulcerated lesion in the lesser curvature of the stomach established the diagnosis of primary gastric adenocarcinoma. When confronted by a patient with impaired function of the cerebral cortex, cranial nerves, and spinal nerve roots that results in progressive neurologic deterioration, leptomeningeal carcinomatosis should be considered and repeated cytologic examinations of spinal fluid should be obtained.