MEN1 and carcinoid tumor: Gastric carcinoid tumors in MEN1/ZES are classified as a Type 2 carcinoid tumor, making up 5–6% of all gastric carcinoids and are similar to Type 1 gastric carcinoids which develop in patients with chronic atrophic gastritis/pernicious anemia (70–80% of all gastric carcinoids), in that both are associated with the presence of chronic hypergastrinemia, but Type 1 gastric carcinoids are seldom malignant, whereas Type 2 gastric carcinoids may be malignant with nodal metastases.