Clinicopathologic and prognostic characterization of poorly differentiated medullary-type gastric adenocarcinoma.

Poorly differentiated medullary-type gastric adenocarcinoma has been reported to differ biologically from poorly differentiated scirrhous adenocarcinoma, and we have characterized the differences in greater detail. Clinicopathologic comparisons were made between the former and latter tumor types as well as well-differentiated gastric adenocarcinoma. Poorly differentiated medullary cancers were smaller, invaded less deeply, and were less likely to arise from the upper part of the stomach than scirrhous cancers. Poorly differentiated medullary cancers less often gave rise to lymph node and peritoneal metastases than scirrhous cancers but more often metastasized to the liver. Venous invasion was more common in medullary than scirrhous or well-differentiated adenocarcinomas. Postoperative survival for patients with poorly differentiated medullary cancers was significantly better than for patients with scirrhous-type cancers but did not differ significantly from survival with well-differentiated adenocarcinoma. The most common cause of death was hematogenous metastasis in patients with medullary or well-differentiated adenocarcinomas, whereas in patients with scirrhous cancer peritoneal metastasis was the most frequent cause. In conclusion, the biologic behavior of poorly differentiated medullary gastric adenocarcinoma was similar to that of well-differentiated adenocarcinoma.