Russell body gastritis: an unusual, tumor-like lesion of the gastric mucosa.

The case of an 80-year-old woman who presented with epigastric symptoms is reported. Upper gastrointestinal endoscopy displayed Candida esophagitis and a localized swelling of the fundic mucosa. Histologic examination of the gastric biopsy showed a distinctive accumulation of numerous uniform plasma cells filled with so-called Russell bodies. On low-power view, the lesion resembled a neoplastic process due to the marked expansion of the lamina propria with distension of fundic glands. However, immunohistochemistry confirmed a polyclonal pattern of the plasma cells. This unusual reactive lesion of the gastric mucosa has only rarely been described and has been termed Russell body gastritis.