Surgery is usually the main treatment for people with pituitary tumors. The most common surgery used to remove pituitary tumors is called transsphenoidal hypophysectomy. In this surgery, the surgeon will make a small cut behind the upper lip and create a hole through one of the bones of the nasal passage in order to reach the pituitary gland. The tumor is then removed. In this kind of surgery, no other part of the brain is touched, and there is no scar that anyone can see. It is common for microadenomas and soft, larger tumors to be removed this way. Another option may be to insert long, thin instruments through the nose, along with a very small camera on the end of a flexible tube (called an endoscope).
If a tumor is very large, or if it has spread to nerves in the area or other parts of the brain, transsphenoidal surgery may not be possible. The surgeon may need to open the brain through the skull, which is called a craniotomy. This is another type of surgery to remove pituitary tumors. This type is only used for large tumors or tumors that have spread to neighboring tissues.
Side effects from surgery are uncommon. However, damage to large arteries, to nearby brain tissue, or to nerves near the pituitary, which rarely can result in brain damage, a stroke, or blindness may occur. Another rare complication is infection of the membranes surrounding the brain (meninges). This is called meningitis (infection and inflammation of the meninges).
A condition that does occasionally occur after surgery for pituitary cancer is diabetes insipidus. This condition results in excessive urination (the urine is very pale, almost clear), excessive thirst, and dehydration. It's caused by a lack of antidiuretic hormone, or ADH, which can be a result of the surgery. Diabetes insipidus generally goes away in a week or two with no treatment. However, a nasal spray that contains vasopressin may be used to treat it.
Levels of other pituitary hormones may be low after surgery. This is less likely after surgery for a small tumor, but when larger tumors are removed, this side effect may be unavoidable. Hormone replacements may be given, if necessary.