Prolactinomas are pituitary adenomas (a monoclonal tumor) that secrete PRL. Like other pituitary adenomas, they can be classified into microadenomas or macroadenomas based on their size (less than 10 mm and greater than 10 mm, respectively). It is important to differentiate between the two because microadenomas are unlikely to compress the optic chiasm, while macroadenomas can compress it resulting in visual field damage which can be irreversible. In addition, macroadenomas, through a mass effect, can compromise other pituitary cells (such as gonadotrophs, thyrotrophs, and ACTH releasing cells). The overwhelming majority of prolactinomas are benign tumors, meaning that they do not metastasize to distant organs. Very few cases of malignant prolactinomas are
reported in the literature; however, prolactinomas can be locally destructive, especially the macroadenomas. In addition to affecting pituitary function by a local mass effect, they can invade the optic chiasm as well as the adjacent cavernous sinus causing cranial nerve neuropathies (CN III, IV, V1, V2, VI). In women, the slightest elevation in prolactin can cause menstrual disturbances. Men, on the other hand, tend to present with symptoms of local mass effect. Physiologic effects of hyperprolactinemia in men (low libido, impotence, and infertility) are less sensitive to the hyperprolactinemia than symptoms in females (oligomenor-rhea or amenorrhea).
When to check a PRL level?
• Any patient (male or female) with galactorrhea
• Any male patient with erectile dysfunction
• Any female patient with amenorrhea or oligomenorrhea
• Patients with neurological symptoms suggestive of pituitary adenomas (severe headaches, visual field changes)
• Patients with incidental pituitary adenomas discovered while imaging the brain for unrelated reasons
Was this article helpful?