5. Lactating Breasts
The pituitary gland produces a wide range of hormones, including prolactin. Prolactin regulates lactation in females, but males also have small amounts of the hormone as well. Men with a pituitary tumor, known as prolactinoma, produce high amounts of estrogen and prolactin.
As a result of this hormone imbalance, affected men start to see the growth of mammary tissue, as well as experience lactation from the nipple. In most cases, the lactation is milky, but in some cases it contains blood.
Men experiencing lactation and gynecomastia must undergo an MRI to determine if there is a tumor pressing down on areas of the pituitary gland, resulting in underproduction of testosterone and overproduction of estrogen and prolactin. However, sometimes an MRI scan may come up with no signs of a tumor because the tumor is too small to register on the scan. In such a case, drug therapy may reduce the size of tumors and prevent lactation.