A pituitary tumor causes symptoms based on:
The type of hormone the tumor is overproducing
The size of the tumor
The effect the tumor has on the normal production of all the other pituitary hormones
This tumor causes symptoms of Cushing's disease, a condition caused by prolonged overproduction of adrenal glucocorticoids and androgens. Symptoms of Cushing's disease include obesity that is most noticeable on the trunk of the body, thin skin, easy bruising, red or purple lines (striae) on the skin of the abdomen, a moon-shaped face, muscle wasting, excess body hair in women, acne, absence of menstrual periods (amenorrhea) and psychiatric symptoms, such as depression and psychosis. Cushing's disease also can trigger osteoporosis, high blood pressure (hypertension), and diabetes.
This tumor occasionally causes a woman who is not pregnant or nursing to produce breast milk, a condition called galactorrhea. Much more often, it causes absent periods (amenorrhea). In men, it causes impotence and decreased sex drive.
Growth hormone-producing tumor
If this tumor develops before puberty, then the child typically has the following symptoms of giantism (also called gigantism): abnormally rapid growth, unusually tall stature, a very large head, coarse facial features, very large hands and feet, and sometimes, behavioral and visual problems. If the tumor develops after puberty, then the person has the following symptoms of acromegaly: thick, oily skin; coarse features with thick lips and a broad nose; prominent cheekbones; a protruding forehead and lower jaw; a deep voice; enlargement of the hands and feet; a barrel-shaped chest; excessive sweating; and pain and stiffness in the joints.
Nonfunctioning pituitary tumor
These tumors do not produce excessive amounts of hormone. They may be found:
Accidentally when magnetic resonance imaging (MRI) of the brain is done for other reasons
If they get large enough to affect the production of other pituitary hormones
If they grow beyond the sella turcica and are causing pressure on the brain or optic nerves that are next to the sella turcica
Prolactin-producing tumors and nonfunctioning tumors can depress the pituitary's ability to make and release other hormones. Sex hormones usually are depressed first followed by thyroid hormone and then adrenal hormones. Symptoms related to low sex hormone levels include loss of sexual drive, erectile dysfunction, and absence of menstrual periods. If a tumor keeps growing, the person may develop fatigue and lightheadedness because the thyroid and adrenal glands aren't functioning properly.
A very large pituitary tumor that grows beyond the sella turcica can cause headaches, loss of peripheral vision and partial paralysis of the eye muscles.