Adenocarcinoma with mixed subtypes
Mixed carcinomas display a mixture of discrete morphologically identifiable glandular (tubular/papillary) and signet-ring/poorly-cohesive cellular histological components. Any discrete histological component should be reported; although the prognostic relevance of the proportion of each component has not been established, preliminary data suggest that any signet-ring/poorly cohesive cellular histological component is associated with a poor prognosis.
Mixed carcinomas are clonal
Caruso ML, Pilato FP, D'Adda T, Baggi MT, Fucci L, Valentini AM, Lacatena M, Bordi C (1989)
Composite carcinoid-adenocarcinoma of the stomach associated with multiple gastric carcinoids and nonantral gastric atrophy.
Cancer 64: 1534-9
Zheng HC, Li XH, Hara T, Masuda S, Yang XH, Guan YF, Takano Y (2008)
and phenotypic divergence has been attributed to somatic mutation in the E-cadherin gene (CDH1), which is restricted to the signet-ring/poorly-cohesive component
Mixed-type gastric carcinomas exhibit more aggressive features and indicate the histogenesis of carcinomas.
Virchows Arch 452: 525-34
Machado JC, Soares P, Carneiro F, Rocha A, Beck S, Blin N, Berx G, Sobrinho-Simões M (1999)
E-cadherin gene mutations provide a genetic basis for the phenotypic divergence of mixed gastric carcinomas.
Lab Invest 79: 459-65