adenoma /ad′ənō″mə/ pl. adenomas, adenomata [Gk, aden + oma] , a benign tumor of glandular epithelium in which the cells of the tumor are arranged in a recognizable glandular structure. An adenoma may cause excess secretion by the affected gland, such as an acidophilic adenoma resulting in an excess of growth hormone. Kinds include acidophilic adenoma, basophilic adenoma, insulinoma, fibroadenoma. −adenomatous, adenomatoid, adj.