Diagnosis of MALT Lymphoma from Surveillance Endoscopy of a Patient with a CDH1 Gene Germline Mutation.

Carriers of the mutated CDH1 gene have an increased risk of developing early-onset signet-ring cell (diffuse) gastric cancer. We present a case of a young patient with a confirmed mutation of the CDH1 gene, who was diagnosed with a gastric marginal zone B-cell lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT lymphoma) from surveillance endoscopy. He underwent Helicobacter pylori eradication treatment and was subsequently submitted to a total prophylactic gastrectomy. The surgical specimen only revealed foci of signet-ring cell carcinoma (SRCC) in situ without lymphoma signs. We highlight here the occurrence of other pathology in high-risk patients as well as its possible influence on the decision to perform gastrectomy.