Signs and Symptoms of Pituitary Tumors

Not all pituitary tumors cause symptoms. But when they do, they can cause many different types of symptoms. The first symptoms often depend on whether the tumor is functional (releasing excess hormones) or non-functional (not releasing excess hormones).

Functional adenomas can cause problems because of the hormones they release. Typically, a functional adenoma makes too much of a single pituitary hormone. These tumors are often found while they are still fairly small (microadenomas). Symptoms from functional adenomas are described below, based on which hormone they secrete.

Tumors that aren’t making excess hormones often become large (macroadenomas) before they are noticed. These tumors cause symptoms when 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 because of an MRI or CT scan done for other reasons. These tumors are now being found more often as more MRI and CT scans of the brain are done. These may be the most common pituitary tumors. As long as they aren’t causing problems, they are typically just watched closely without needing treatment.

Large tumors (macroadenomas) and pituitary carcinomas

Pituitary macroadenomas (benign tumors larger than 1 cm) and carcinomas (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:

  • Blurred or double vision
  • Loss of peripheral vision
  • Sudden blindness
  • Headaches
  • Facial numbness or pain
  • Dizziness
  • Loss of consciousness (passing out)

Vision problems occur when the tumor “pinches” the nerves that run between the eyes and the brain. Sudden loss of vision, 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. This can lead to low levels of some body hormones such as cortisol, thyroid hormone, and sex hormones. Depending on which hormones are affected, the symptoms might include:

  • Nausea
  • Weakness
  • Unexplained weight loss or weight gain
  • Feeling cold
  • Feeling tired or weak
  • Menstrual changes or loss of menstrual periods in women
  • Erectile dysfunction (trouble with erections) in men
  • Decreased interest in sex, mainly in men

Diabetes insipidus: Large tumors can sometimes press on the posterior pituitary, causing a shortage of the hormone vasopressin (also called anti-diuretic hormone or ADH). This can lead to diabetes insipidus. In this condition, too much water is lost in the urine, so the person urinates often and becomes very thirsty as the body tries to keep up with the loss of water. If left untreated, this can cause dehydration and abnormal blood mineral levels, which can lead to coma and even death. Fortunately, this condition is easily treated with a drug called desmopressin, which replaces the vasopressin. (Diabetes insipidus is not related to diabetes mellitus, in which people have high blood sugar levels.)

Growth hormone-secreting adenomas

The major symptoms from these tumors are caused by having too much growth hormone (GH). These effects are quite different in children and adults.

In children, high GH levels can stimulate the growth of nearly all bones in the body. The medical term for this condition is gigantism. Its features typically include:

  • Being very tall
  • Very rapid growth
  • Joint pain
  • Increased sweating

In adults, the long bones (especially in the arms and legs) can’t grow any more, even when GH levels are very high. But bones of the hands, feet, and skull can grow throughout life. Adults with GH-secreting adenomas don’t grow taller and develop gigantism. Instead, they develop a different condition called acromegaly. The signs and symptoms are:

  • Growth of the skull, hands, and feet, leading to increase in hat, shoe, glove, and ring size
  • Deepening of the voice
  • Change in how the face looks (due to growth of facial bones)
  • Wider spacing of the teeth and protruding jaw (due to jawbone growth)
  • Joint pain
  • Increased sweating
  • High blood sugar or even diabetes mellitus
  • Kidney stones
  • Heart disease
  • Headaches
  • Thickening of tongue and roof of mouth, leading to sleep disturbances such as snoring and sleep apnea (pauses in breathing)
  • Thickened skin
  • Increased growth of body hair

Many of these changes can occur very slowly, and people might not notice them until they look at an old picture of themselves (or try to put on a hat or ring they haven’t worn in many years).

Corticotropin (ACTH)-secreting adenomas

High ACTH levels cause the adrenal glands to make steroid hormones such as cortisol. Having too much of these hormones causes symptoms that doctors group together as Cushing’s syndrome. When the cause is too much ACTH production from the pituitary it is termed Cushing’s disease. In adults, the symptoms can include:

  • Unexplained weight gain (mostly in the chest and abdomen)
  • Purple stretch marks on the abdomen
  • New or increased hair growth (on the face, chest, and/or abdomen)
  • Swelling and redness of the face
  • Acne
  • Fat areas near the base of the neck
  • Moodiness or depression
  • Easy bruising
  • High blood sugar levels or even diabetes mellitus
  • High blood pressure
  • Decreased interest in sex
  • Changes in menstrual periods in women
  • Weakening of the bones, which can lead to osteoporosis or even fractures

Most of these symptoms can also occur in children. Children with Cushing’s disease may also stop growing and have problems with school performance.

Prolactin-secreting adenomas (prolactinomas)

Prolactinomas are most common in young women and older men. In women before menopause, high prolactin levels cause menstrual periods to become less frequent or to stop. High prolactin levels can also cause abnormal breast milk production, called galactorrhea. In men, high prolactin levels can cause breast growth, erectile dysfunction (trouble with erections), and loss of interest in sex.

If the tumor continues to grow, it can press on nearby nerves and parts of the brain, which can cause headaches and vision problems. In females who don’t have periods (such as girls before puberty and women after menopause), prolactinomas might not be noticed until they cause these symptoms.

Thyrotropin (TSH)-secreting adenomas

These rare tumors make too much thyroid-stimulating hormone (TSH), which then causes the thyroid gland to make too much thyroid hormone. This can cause symptoms of hyperthyroidism (overactive thyroid), such as:

  • Rapid heartbeat
  • Tremors (shaking)
  • Weight loss
  • Increased appetite
  • Feeling warm or hot
  • Sweating
  • Trouble falling asleep
  • Anxiety
  • Frequent bowel movements
  • A lump (enlarged thyroid) in the front of the neck

Gonadotropin-secreting adenomas

These uncommon tumors make luteinizing hormone (LH) and/or follicle-stimulating hormone (FSH). This can cause irregular menstrual periods in women or low testosterone levels and decreased interest in sex in men.

Many gonadotropin-secreting adenomas actually don’t make enough hormones to cause symptoms, so they are basically non-functional adenomas. These tumors may grow large enough to cause symptoms such as headaches and problems with vision before they are detected (see the symptoms for large tumors above).

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: May 8, 2014 Last Revised: December 17, 2014

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