What types of pituitary tumors are there?

Normally, cells in the body will grow and divide to replace old or damaged cells. This growth is highly regulated, and once enough cells are produced to replace the old ones, normal cells will stop dividing. Tumors occur when there is an error in this regulation, and cells continue to grow in an uncontrolled manner. Tumors can either be benign or malignant. Benign tumors represent uncontrolled growth; however, unlike malignant tumors, they typically do not invade into surrounding tissues or break off and spread beyond where they started. Malignant tumors, however, will grow uncontrolled in such a way that they invade and damage other tissues around them. They also gain the ability to break off from where they started and spread to other parts of the body, usually through the blood stream or through the lymphatic system where the lymph nodes are located.

The vast majority of tumors in the pituitary gland are benign, and most of these are pituitary adenomas (see below). Other types of tumors (both benign and malignant) can develop in the pituitary gland, and these include teratomas , germinomas , and choriocarcinomas . Although malignant cancers can develop in the pituitary gland, they are very rare. In fact, only about 100 cases of malignant pituitary cancer have been reported in the medical literature.

What is a pituitary adenoma?

Pituitary adenomas are benign growths of glandular tissue that almost always grow from the anterior lobe of the pituitary gland. Pituitary adenomas can be either non-secreting adenomas, meaning that they do not produce excess levels of hormones, or they can be secreting adenomas, meaning that they produce an excessive level of one or more of the hormones normally produced by the pituitary gland.