An Unexpected Cause of Iron Deficiency Anemia: Synchronous Development and Diagnosis of a Rare Gastric Collision Tumor

Abstract

A 75-year-old man with diabetes and hypertension presented with chest pain and was found to have a ST-elevation myocardial infarction. He was taken to the cardiac catheterization lab for coronary angiography. Following the procedure, he described a several week history of post-prandial epigastric discomfort, for which he was taking naproxen. He denied symptoms of gastrointestinal bleeding. Laboratory data showed iron deficiency anemia (ferritin: 15 ng/mL, hemoglobin: 11.3 g/dL). Esophagogastroduodenoscopy (EGD) demonstrated an irregular, linear, non-bleeding 3 cm ulcer in the stomach body extending into the antrum with a hard consistency (Figure 1), as well as an irregular, cratered, non-bleeding 3 cm ulcer in the gastric cardia with heaped-up margins (Figure 2). Biopsies of the ulcer in the body revealed an invasive moderately differentiated gastric adenocarcinoma (Figure 3, top left and right). Biopsies of the ulcer in the cardia revealed diffuse large B-cell lymphoma (Figure 3, bottom left and right). Histopathology was negative for Helicobacter pylori (H. pylori). The patient underwent subsequent coronary artery bypass grafting and is following with an oncologist for further management. The EGD and histopathologic findings demonstrated synchronous development of a rarely reported collision tumor: gastric adenocarcinoma and diffuse large B-cell lymphoma, each having a distinct endoscopic appearance. Synchronous tumors in the stomach are uncommon. The majority of synchronous malignancies are gastric adenocarcinomas and mucosa associated lymphoid tissue (MALT) lymphomas.1 There have been less than 10 known published reports of the synchronous development of gastric adenocarcinoma and diffuse large B-cell lymphoma.1 This case is also unusual, as H. pylori was not detected on histology. This vignette is significant both for the rarity of the final diagnoses, as well as the reminder that the practicing gastroenterologist provide a thorough endoscopic examination and perform appropriate mucosal sampling, even in the presence of an already identified abnormality. These malignancies would likely have been diagnosed at a later stage had the patient not presented with acute coronary syndrome and undergone endoscopic evaluation for iron deficiency anemia.Figure: Gastric Body Adenocarcinoma.Figure: Gastric Cardia Diffuse Large B-Cell Lymphoma.Figure: Clockwise, from Top Left: Gastric Body Adenocarcinoma (H&E stain, 40x), Invasive Neoplastic Glands (H&E stain, 200x), Gastric Cardia Large Cell Lymphoma (H&E stain, 400x), Diffuse B-Cell Infiltrates Entrapping Benign Gastric Glands (H&E stain, 40x).