Early gastric adenocarcinoma arising within foveolar-type dysplasia in a patient with Muir-Torre variant Lynch syndrome

Excerpt

Lynch syndrome (LS) is an autosomal dominant condition defined by the presence of a germline mutation in a DNA mismatch repair (MMR) gene with associated loss of expression of the MLH1, MSH2, MSH6, and/or PMS2 proteins, which function to correct base substitution errors during DNA replication [1]. Inactivation of this MMR system results in the accumulation of mutations among microsatellite sequences across the genome, ultimately leading to development of microsatellite instability (MSI). LS is the most common cause of inherited colorectal cancer and also predisposes individuals to developing other cancers, including endometrial cancers. Screening and surveillance guidelines are well established to reduce the risk of these cancers. LS patients also carry a 1–13% increased risk of developing gastric cancer compared to the general population, making gastric cancer the second most common extracolonic cancer in LS patients after endometrial cancer [2]. There are no studies that have evaluated the effectiveness of screening and surveillance for gastric cancer in LS patients. However, screening for gastric cancer in LS is often done on a case-by-case basis, taking into account family cancer history, and generally includes baseline esophagogastroduodenoscopy (EGD) with gastric biopsy starting at age 30–35 years, as well as eradication of any detected Helicobacter pylori [1‐3, 17]. …