Helicobacter pylori-negative Russell body gastritis: case report.

Russell body gastritis is an unusual form of chronic gastritis characterized by the permeation of lamina propria by numerous plasma cells with eosinophilic cytoplasmic inclusions. Very few cases have been reported in the literature; the majority of which have shown Helicobacter Pylori (H. pylori) infection, thus suggesting a correlation between plasma cell presence and antigenic stimulation by H. pylori. We present a case of Russell body gastritis in a 78-year-old woman who was undergoing esophagogastroduodenoscopy for epigastric pain. Gastric biopsy of the gastroesophageal junction showed the presence of cells with periodic acid-Schiff-positive hyaline pink bodies. Giemsa staining for H. pylori infection was negative, as well as immunohistochemical detection. The cells with eosinophilic inclusions stained positive for CD138, CD79a, and κ and lambda light chains, which confirmed plasma cell origin. In particular, κ and lambda light chains showed a polyclonal origin and the patient was negative for immunological dyscrasia. The histological observations were confirmed by ultrastructural examination. The cases reported in the literature associated with H. pylori infection have shown regression of plasma cells after eradication of H. pylori. Nothing is known about the progression of H. pylori-negative cases. The unusual morphological appearance of this type of chronic gastritis should not be misinterpreted during routine examination, and it should be distinguished from other common forms of chronic gastritis. It is mandatory to exclude neoplastic diseases such as gastric carcinoma, lymphoma and plasmocytoma by immunohistochemistry and electron microscopy, which can help with differential diagnosis. The long-term effects of plasma cells hyperactivation are still unknown, because cases of gastric tumor that originated in patients affected by Russell body gastritis have not been described in the literature. We are of the opinion that these patients should be scheduled for endoscopic surveillance.