An aenoma is a collection of growths (-oma) of glandular origin. Adenomas can grow from many organs including the colon, adrenal, pituitary, thyroid, etc. These growths are benign, although over time they may progress to become malignant, at which point they are called adenocarcinomas. Though adenomas are benign, they have the potential to cause serious health complications by compressing other structures (mass effect) and by producing large amounts of hormones in an unregulated, nonfeedback-dependent manner (paraneoplastic syndrome).