Background: Russell body gastroesophagitis is a rare entity characterized by the accumulation of immunoglobulins within the cytoplasm of plasma cells. Case Report: Here, we present the case of a 41-year-old male with history of gastroesophageal reflux disease who presented with nausea, vomiting, and altered mental status. Candida esophagitis was noted on upper endoscopy. After treatment, a surveillance endoscopy revealed salmon colored mucosa in the distal esophagus and mild gastric erythema. The biopsy confirmed Barrett's esophagus that was negative for dysplasia and mild chronic inactive gastritis. Interestingly, diffusely infiltrating Russell body-containing plasma cells (Mott cells) were present in the distal esophagus and extending into the gastric cardia. The Mott cells were highlighted on CD138 immunostaining and Periodic acid-Schiff stain. Immunostaining for cytokeratin AE1/AE3 was negative. There was no evidence of Helicobacter pylori organisms on the gastric mucosa. Conclusion: This is the first report on Russell body-containing plasma cells diffusely involving both esophagus and gastric cardia with concurrent Barrett's esophagus.