Gastric Adenocarcinoma, Diffuse Type (Linitis Plastica; Signet Ring Cell Carcinoma)
Chronic inflammatory cells are scattered in between signet ring cells. The intestinal and diffuse (signet ring cell) subtypes of gastric carcinomas follow different molecular genetic pathways. Mutations in CDH1 gene which codes for E-cadherin protein are seen in the diffuse subtype of gastric cancers. E-cadherin is a component of adherens junction and promotes adhesion between cells. Loss of E-cadherin function results in diffuse growth of tumor cells. CDH1 mutations are also seen in lobular carcinoma of breast, another tumor with diffuse growth pattern.