Massive gastric polyposis associated with a germline SMAD4 gene mutation

Juvenile polyposis syndrome (JPS) is a rare autosomal dominant disorder characterized by the development of multiple hamartomatous polyps in the gastrointestinal tract. Polyps are most common in the colorectum (98% of patients) and the stomach (14%). Causative mutations for JPS have been identified in two genes to date, SMAD4 and BMPR1A. SMAD4 mutations are associated with a higher incidence of gastric polyposis. In this case report, we describe two patients with massive gastric polyposis associated with a SMAD4 mutation. Both presented with anaemia and both had colonic polyps. Initial endoscopic findings revealed giant rugal folds suggestive of Ménétrier disease. However, as other possible gastropathies could not be differentiated on the basis of histology, a definitive diagnosis of JPS required additional mutation analysis. In patients with polyposis predominant in or limited to the stomach, establishing a diagnosis based solely on the pathological features of polyps can be challenging due to difficulties in differentiating JPS from other hypertrophic gastropathies. Mutation analysis should be considered early in the diagnostic process in cases of suspected juvenile polyposis, thus facilitating rapid diagnosis and adequate follow-up.