Zollinger–Ellison Syndrome
High-power view of gastric mucosa in a patient with Zollinger–Ellison syndrome. Note the large increase in the number of parietal cells.

Source: Rosai: Surgical Pathology 9th edition
High-power view of gastric mucosa in a patient with Zollinger–Ellison syndrome. Note the large increase in the number of parietal cells.

Source: Rosai: Surgical Pathology 9th edition