Mixed gastric carcinoma with intestinal and cribriform patterns: a distinctive pathologic appearance associated with poor prognosis in advanced stages and a potential mimicker of metastatic breast carcinoma.

Gastric adenocarcinoma is characterized by marked heterogeneity at cytological and architectural level and frequently shows overlap between microscopic patterns. This article describes a peculiar pattern of gastric adenocarcinoma, previously unreported, that combines intestinal type adenocarcinoma with areas of cribriform pattern that resembles both architectural and cytological in situ ductal carcinoma of the breast and to the best of the authors' knowledge, there are no earlier reports of this pattern in the stomach, which has been named "gastric carcinoma with cribriform component (CGA). The authors analyzed 12 cases of intestinal type adenocarcinoma with areas at least 20% of cribriform pattern (range from 20% to 90%) that was present in 9% of intestinal type gastric adenocarcinomas in their institution. There is slight predilection for male sex, and the median age of presentation is 55.8 years. The phenotype by immunohistochemistry is the same as with conventional (non-CGA) carcinomas. CGA shows more frequent lymphovascular invasion (P = .039), perineural invasion (P = .027) and resembles both in situ and invasive cribriform carcinoma of the breast. In clinical stage III the overall 3-year survival of CGA was worse than those with non-CGA component (38.6% vs 25%; 3-year survival, P = .010) and proves to be an independent adverse factor for overall survival in a multivariate analysis. Compared with conventional gastric carcinomas, CGA is deep infiltrating, has more nodal metastases, more lymphovascular and perineural invasion, and has decreased overall survival. Thus, proper recognition and report is important, even in small biopsies or small foci.