PITUITARY NEOPLASMS: GENERAL CONSIDERATIONS



Pituitary neoplasms are usually benign and slow growing and may remain undetected for many years. Neurologic symptoms, principally headache and visual disturbances, maybe the first manifestations, or the patient may present with findings consistent with pituitary insufficiency or with excessive secretion of any of the anterior pi­tuitary hormones. Not infrequently, the presence of a pituitary neoplasm may be discovered in an asymptomatic patient in whom a skull radiograph is obtained for unrelated reasons.

Because of the close proximity of the optic nerves and optic chiasm, visual field defects are often the principal neurologic findings when a pi­tuitary tumor extends beyond the confines of the sella turcica. Typically, this is manifested as bi­temporal hemianopsia, often beginning in the upper quadrants of the visual field. Extraocular nerve palsies can also occur when the tumor en­larges laterally into the cavernous sinus. Head­ache, due in some cases to increased intracranial pressure secondary to obstruction of outflow of cerebrospinal fluid from the third ventricle, may also be a prominent complaint with large tumors. Headache is also common with smaller tumors.

Decisions regarding the management of pitui­tary tumors should be made in collaboration with a neurosurgeon. The optimal approach usually depends upon the size, location, and whether or not the tumor is endocrinologically active. Large tumors that impinge on extrasellar structures usu­ally require surgical management whether or not they are secretory in nature. Smaller tumors that are actively secreting anterior pituitary hormones, such as prolactinomas, can often be managed medically with bromocriptine (see below).

The finding of an enlarged sella turcica does not of itself indicate the presence of a pituitary tumor. Many patients with an enlarged sella, particularly obese women, have the so-called empty sella syn­drome, in which the pituitary gland is displaced by cerebrospinal fluid that enters the sella via a defect in the diaphragm above the sella. These pa­tients rarely have endocrinologic abnormalities. Distinction from pituitary tumor is usually pos­sible with high-resolution CT scans.