This is a rare and interesting clinical report of an individual with MEN1 and a constellation of neuroendocrine, oncological, and autoimmune diseases: pernicious anemia with type 1 gastric NET and lung metastases, lymphocytic thyroiditis with concurrent MALT lymphoma, macroprolactinemia, and gonadotropin deficiency (possibly due to lymphocytic hypophysitis), parathyroid adenomas with lymphocytic infiltration and positive antiCaSR antibodies, and breast carcinoma. This evidence concerns the gene MEN1 and breast carcinoma.