A clinicopathologic study of mucinous adenocarcinoma of the stomach

Background. Mucinous adenocarcinoma of the stomach is a rare histologic type of gastric adenocarcinoma and its features are still controversial. We attempted to clarify the clinicopathologic characteristics of this histologic type. Methods. We reviewed the records of 112 patients with mucinous adenocarcinoma of the stomach (MUC) and 4160 patients with nonmucinous gastric adenocarcinoma (NMUC) for factors including age; sex; tumor location, size, and depth; lymph node metastasis; lymphatic or venous permeation; peritoneal dissemination; liver metastasis; and survival rate. We also investigated the relationship between cancer depth and lymph node metastasis. Statistical analysis included χ ² and Student's t -tests. Survival rates were calculated by the Kaplan-Meier method and analyzed by the log rank test. Results. MUC was found mostly in younger patients, in the lower part of the stomach and was of larger size, invading to or beyond the muscularis propria, positive for lymph node involvement, and associated with peritoneal dissemination. The overall 5-year survival rate in patients with MUC was lower than that in NMUC patients, because the MUC patients more frequently had advanced stage disease; however, the survival rates in the two groups did not differ significantly. As for the relationship between cancer depth and lymph node involvement, the frequency of lymph node metastasis increased when invasion reached the submucosa in patients with MUC compared with those with NMUC while the frequency of lymph node metastasis increased in the muscularis propria in patients with NMUC compared with those with NMUC. Conclusion. MUC was characteristically found in younger patients, at lower sites, at an advanced stage, and with peritoneal dissemination; MUC had a poor prognosis. Lymph node metastasis should be suspected when MUC invades to the submucosa or deeper. Received: March 14, 2001 / Accepted: June 18, 2001