Updated: September 29, 2019
Pituitary tumors are often called pituitary adenomas cause symptoms when they are functional. Because of the excessive hormones produced by functional tumors they can cause symptoms whereas non-functional tumors often become large (macroadenomas) before they are noticed. This is because these tumors do not cause symptoms until they press on nearby nerves, parts of the brain, or other parts of the pituitary.
Non-functional adenomas that cause no symptoms are sometimes found when an MRI or CT scan done for other reasons. They are often just watched closely without needing treatment as long as they are not causing problems.
Most of the time, a functional adenoma makes too much of a single pituitary hormone and the symptoms from these adenomas are based on which hormone they make. Therefore these tumors can be found while they are still fairly small (microadenomas).
Benign tumors larger than 1 cm are known as macroadenomas. These tumors or cancers whether functional or not, can be large enough to press on nearby nerves or parts of the brain. This can lead to symptoms such as:
When the tumor pinches the nerves that run between the eyes and the brain, vision problems occur. Sudden blindness, loss of consciousness, and even death can result from sudden bleeding into the tumor.
Macroadenomas and pituitary carcinomas can also press on and destroy the normal parts of the pituitary gland causing a shortage of one or more pituitary hormones. When the pitutary galnd is pressed it can not produce one or more require amount of body hormones such as cortisol, thyroid hormone, and sex hormones which can cause symptoms. Depending on which hormones are affected, symptoms might include:
When large tumors press on the posterior part of the pituitary, it causes shortage of the hormone vasopressin which is also called anti-diuretic hormone or ADH. This can lead to diabetes insipidus, a condition in which too much water is lost in the urine. The person urinates often and has to drink more water as the body tries to keep up with the loss of water.
Left untreated, this condition can cause dehydration and altered blood mineral levels, which can lead to coma and even death. Desmopressin, which replaces the vasopressin are used for the treatment of diabetes insipidus. Diabetes insipidus is not related to diabetes mellitus, in which people have high blood sugar levels.
Too much growth hormone (GH) produced by this adenoma can cause symptoms which are quite different in children and adults. In children, high GH levels can develop gigantism in which the growth of nearly all bones in the body are stimulated.
In adults, even when GH levels are very high the long bones especially in the arms and legs can not grow any more resulting in gigantism. But the bones of hands, feet, and skull/face can grow throughout life causing a condition called acromegaly. Signs and symptoms are:
High ACTH levels cause the adrenal glands to make steroid hormones such as cortisol leading to Cushing's syndrome. When too much ACTH is produced from the pituitary it is called Cushing's disease. In adults, the symptoms can include:
Most of these symptoms can also occur in children can effect the growth.
Prolactinomas are most common in young women and older men. Symptoms may include:
If the tumor continues to grow, it can press on nearby nerves and parts of the brain, which can cause headaches and vision problems.
Too much thyroid-stimulating hormone (TSH) is produced leading to production of too much thyroid hormone by the thyroid gland. This can cause symptoms of hyperthyroidism such as:
High levels of luteinizing hormone (LH) and/or follicle-stimulating hormone (FSH) can cause irregular menstrual periods in women or low testosterone levels and decreased interest in sex in men. Most of the gonadotropin-secreting adenomas do not make enough hormones to cause symptoms. Therefore they are basically non-functional adenomas. These tumors may grow large enough to cause symptoms such as headaches and vision problems when press on nearby nerves and parts of the brain before they are found.