The Visible Stomach: Elusive Diffuse-Type Adenocarcinoma Presents With Gastric Outlet Obstruction.

The diagnosis of diffuse-type gastric cancers may be challenging due to their submucosal infiltration. A male in his early 60s was diagnosed with signet-ring cell adenocarcinoma of the diffuse type based on a biopsy from a perforated gastric ulcer. Postoperative workup was negative, including repeated esophagogastroduodenoscopy, gastric biopsies, tumor markers, computed tomography (CT), and positron emission tomography (PET). Six months after the operation, the patient presented to our center with abdominal discomfort and nausea. The clinical examination showed an enlarged visible stomach due to gastric outlet obstruction. The patient underwent total gastrectomy after confirmation of malignancy using an intraoperative frozen section. However, the tumor was already advanced locally and regionally. Confirmed malignancy in biopsies from perforated gastric ulcers should be never considered false positivity. To avoid missing a diffuse gastric cancer, endoscopic biopsies should be obtained using advanced techniques such as submucosal dissection under endosonographic guidance.