Prolactinoma

Prolactinomas are benign adenomas composed of lactotrophic cells of the pituitary gland that secrete excess amounts of the polypeptide hormone prolactin. They represent the most commonly diagnosed type of functioning pituitary tumour - that is, one that generates a clinical syndrome of hormone excess - and are a common cause of infertility in women. Lactotroph cells normally constitute about 20% of the cells in the normal human anterior pituitary gland, but their number and size increase during pregnancy. They are thought to derive from an embryonic mammosomatotroph cell precursor that produces both prolactin and growth hormone (1). In this chapter we will review briefly the key elements of prolactin physiology, and then consider the clinical presentation, diagnosis, treatment and monitoring of prolactinomas.