Leptomeningeal carcinomatosis originating from gastric cancer: report of eight cases and review of the literature.

Leptomeningeal carcinomatosis caused by metastatic gastric adenocarcinoma has been rarely reported in the United States. We present eight cases of patients with gastric cancer who subsequently developed meningeal carcinomatosis. On average, patients presented with symptoms of leptomeningeal disease (LMD) 12 months after the initial diagnosis. Distinguishing features include a predominance of poorly differentiated histology, typically associated with signet ring cells, a diffuse pattern of primary organ involvement, systemic dissemination in the form of peritoneal carcinomatosis, and development of LMD despite responsiveness to chemotherapy elsewhere in the body. The natural history of these patients, with or without treatment, was uniformly poor. Although previously thought to be an extremely rare event, LMD in the setting of gastric adenocarcinoma may be a problem on the rise, possibly due to the increasing survival times of patients. Physicians should have a high index of suspicion since no single test can reliably diagnose this entity in all cases. Furthermore, the striking clinical picture of patients with LMD raises interesting questions about the biology and metastatic behavior of certain subclasses of gastric cancer.