Russell body gastritis presented as a colliding lesion with a gastric adenocarcinoma: A case report

Russell body gastritis (RBG) is a rare gastric mucosal lesion comprising numerous Russell body-containing plasma cells (Mott cells). Early gastric cancer was discovered during a routine health checkup of a 55-year-old man treated with esophagogastroduodenoscopy. Endoscopic submucosal dissection and a histological examination revealed well-differentiated tubular adenocarcinoma and RBG. The two lesions were contiguous but not intermingled. Helicobacter pylori infection was also identified. Immunohistochemically, Mott cells of RBG manifested λ-light chain restriction. However, polymerase chain reaction analysis did not reveal IgH gene rearrangement. Epstein–Barr virus encoded RNA in situ hybridization showed no Epstein–Barr virus infection in cancer or Mott cells. Thus, two distinct RBG features are demonstrated: coexistence with early gastric cancer and λ-light chain restriction. The proliferation of Mott cells with light chain restriction may be due to a chronic hyperinflammatory response caused by H. pylori infection. However, it is unclear whether RBG is associated with gastric carcinoma.