If you drew a line straight back between your eyes, you would hit the pituitary gland in about three inches. Though only about the size of a pea, the pituitary is a master regulator of hormone systems throughout the body. It’s also a fairly common origin of tumors. One in every 10,000 people will be diagnosed with a neuroendocrine tumor originating in the pituitary; one in five people will develop a pituitary mass without knowing it. Most of these pituitary masses aren’t cancer – they become dangerous only when they affect pituitary function or grow large enough to squeeze against other nearby structures, often creating headaches or affecting vision. But some pituitary masses are cancer. Knowing the difference can be tricky and treating these diverse pituitary tumors can be especially challenging.