Disorders of the anterior pituitary gland and the posterior pituitary gland are usually associated with excess or deficient hormone synthesis and secretion. Tumors of the anterior pituitary gland are mutually common contracting a small percentage of all brain tumors. In autopsies done, when the cause of death is not limited to any group of diagnoses, almost one third of those examined have small pituitary tumors.
Predisposing factors are uncommon. Persons with untreated hypofunction of end organs such as the gonads, adrenals or thyroid may be at risk. They may develop hyperplasia initially and then autonomously functioning tissue that secretes the stimulating hormone for the hypofunctional gland. Long term malnutrition, particularly if it is severe, can cause excess growth hormone secretion. These events are logical exit of the negative feedback system, in which the pituitary gland attempts in vain to restore homeostasis by ever-increasing hormone production.
Malignant tumor symptoms include neurological findings like headache caused by pressure on the dura. These nonspecific headings are inconsistent in regard to location and degree of relief from analgesics. The pain is usually dull, unaffected by position, and not accompanied by nausea and visual changes. Sudden relief may accompan Rupture of the dura. With significant escalation, pressure may be applied to the optic chiasm causing bitemporal hemianopsia or loss of vision from the outer or lateral half of each eye. Papilledema may also be a finding. If the tumor becomes large enough to cause pressure on the hypothalamus, unstable body temperature, excessive appetite and psychiatric disorders may develop.
Most patients with pituitary tumors will undergo tumor treatment like surgery, radiation therapy or both. A transsphenoidal hypophysectomy is the removal of a portion or the entire anterior pituitary gland using a route through the sphenoid sinus. It is preferred approach for most anterior pituitary tumors because it eliminates manipulation of the brain substance that occurs with previously used frontal craniotomy approach and there is no visible scar.
The incision is made at the base of the upper lip where it joins the gum. After the floor of the sella tursica is exposed, the dura mater over the pituitary gland is opened and the tumor is removed. A small piece of fascia and muscle obtained from the thigh of the patient is used to secure a tight seal at the floor of the sella tursica and prevent cerebrospinal fluid.
The sphenoid sinus is not packed. The nostrils are packed with vaseline gauze to facilitate proper reapproximation of the nasal mucosa. Nasopharyngeal airways may be placed prior to packing to allow the patient to breathe through the nose during the immediate postoperative period. The nasal packing is usually removed 2 days after surgery.
Alterations in pituitary function after pituitary surgery will vary according to the preoperative hormone dysfunctions of the patient, amount of pituitary tissue damaged or removed, and extent of postoperative edema in the region of the hypothalamus and the pituitary. Cortisol may need to be replaced at levels associated with major stressors during surgery. Surgery is an effective pituitary tumor treatment. It is one of the methods that patients and the medical team decide to do.