The lining epithelium of mucinous cystadenomas usually consists of simple non-stratified columnar cells resembling gastric foveolar or intestinal epithelium. It may be thrown into folds or simple papillary formations. Less commonly, it is endocervical type. The intestinal epithelium is admixed with goblet cells, Paneth cells, endocrine cells, as well as signet ring cells (rare cases). The lining cells are capable of producing intestinal enzymes (lipase, trypsin, and amylase) as well as peptide hormones (serotonin, ACTH, gastrin, and somatostatin).