Pituitary tumors

What are pituitary tumors?

Pituitary tumors are tumors that develop from the tissues of the pituitary gland, which is a small pea-size structure present at the base of the brain. This gland produces several hormones, which, in turn, control the hormone production by several major glands in the body, such as the thyroid, adrenals, ovaries, and testes, and milk production by the mammary glands after childbirth. The majority of tumors that develop in the Pituitary Gland are non-cancerous (benign). Such pituitary tumors are called adenomas. Adenoma could result in abnormally high or unusually low hormone formation.

Is a pituitary tumor a medical emergency?

Pituitary tumors are not a medical emergency. But, a rare scenario wherein there is sudden bleeding into the Pituitary Gland is called Pituitary Apoplexy. This causes a sudden, unbearable headache and a severe drop in blood pressure. This could be fatal and hence needs emergency hospital admission.

Types

Pituitary tumors can be categorized based on the hormones they produce:

• Nonfunctional adenomas: These are the most common form of pituitary tumors, and they don’t produce any hormones
• Prolactin producing tumors
• ACTH producing tumors
• Growth hormone-producing tumors

Causes

The exact cause of pituitary tumors is still unknown, but genetic or cell mutations are assumed to be responsible for pituitary tumors as well. However, the cause of these mutations is not yet known.

Risk factors

There are no known risk factors for pituitary tumors, but a family history of disease of the endocrine system, such as Multiple Endocrine Neoplasia (MEN), increases the risk of a pituitary tumor.

Signs & symptoms of pituitary tumors

A pituitary tumor could develop from hormone-producing cells of the pituitary gland or other cells that do not produce hormones. Hormone disturbance can happen in two ways:

• When hormone forming cells give rise to a pituitary tumor
• When other cells give rise to a pituitary tumor, which grows so big that it compresses hormone forming cells

Common symptoms which develop due to the pressure exerted by the tumor are:

• Headache
• Disturbances in vision, such as loss of peripheral vision in which the individual loses the outer part of the vision

Symptoms due to hormone imbalance are:

• Deficiency symptoms:
  • Vomiting or an abnormal urge to vomit (nausea)
  • Feeling weak for most of the day
  • Unable to tolerate low temperatures at all
  • Menstrual periods becoming less frequent or, at times, completely stopping.
  • Producing more volume of urine in a day
  • Putting on weight, though the person doesn’t do anything towards it
  • Problems in sex life
• Hormone specific symptoms:
  • Adrenal hormone: The hormone that influences the Adrenals is ACTH. When there is an excess of ACTH.
  • The body fat is redistributed. This means fat in the arms and legs drops drastically while an abnormal amount of fat is deposited in the face and midsection.
  • This results in an unusually round face commonly called a ‘moon face’. Excess fat on the back gives the appearance of a hump.
  • The bones become weak.
  • High blood sugar and high blood pressure
  • Purple colored stretch marks may develop on the tummy.
• Growth hormone: Excess of this hormone causes unusually rapid growth in children and adolescents. In adults, the following may be seen:
  • Increased size of hands and feet
  • Abnormal and coarse facial features
  • Poor alignment of teeth
  • High blood sugar
  • Heart diseases
• Prolactin: Excess prolactin can affect males and females differently,
  • In males: There could be a loss of interest in sex, inability to have an erection, decreased sperms in the semen, and abnormal growth of breast tissue.
  • In women: Milk leaks from the breast, untimely or unpredictable periods, and in some women, menstrual cycles may completely stop
• Thyroid hormone: Excess of thyroid hormone could result in,
  • Increased heartbeat
  • Unusually high sweating
  • Weight loss through the person doesn’t put in any effort regarding this.
  • Loose stool
  • Feeling anxious or restless for most of the day

Investigations

Pituitary tumors are very difficult to diagnose. The reason is that the symptoms it causes are similar to those caused by other medical conditions. Moreover, pituitary adenomas grow slowly, so they may not cause symptoms for a long time, though they are present in the body. In many people, pituitary tumors are discovered accidentally when scans are performed to diagnose other conditions. The following investigations are commonly done for pituitary tumors:

• Blood and Urine tests: The hormones or their breakdown products circulate in the blood or are eliminated from the body through urine. Thus, specific blood and urine tests help in diagnosis.
• Brain scans: Imaging modalities like CT and MRI are crucial in detecting a Pituitary Adenoma.
• Assessment of vision: Pituitary Adenomas almost always affect the vision. Thus, these tests are essential to know the impact of the tumor.

Diagnosis

A diagnosis of pituitary tumors is established based on medical history, clinical evaluation, and results of the investigations done.

Pituitary tumor treatment options

Medical treatment

Medications help in preventing the formation of excess hormones. In some cases, the tumor can also be reduced in size. The commonly used medicines are:

• Mifepristone: It is used in people with a pituitary tumor that produces excess ACTH. This medicine prevents the ACTH from showing its effect on the tissues. This is particularly useful for people with diabetes.
• Pasireotide: It is a medicine that has been developed recently. It works by blocking the formation of ACTH in the pituitary tumor.
• Cabergoline and Bromocryptine: These are medicines that block the production of prolactin from a Pulmonary tumor.
• Octreotide and Lanreotide: These belong to a class of medicines called Somatostatin analogs. These can stop the Pituitary tumor from producing excess growth hormone. They are given in an injection form once every 4 weeks.
• Pegvisomant: It is a medicine that blocks the action of growth hormones in body tissues. Thus, all the symptoms that growth hormones can cause subside.
• Pituitary hormone replacement: When a significant portion of the pituitary gland has been removed, or radiation has damaged a major portion of the gland, the hormones necessary for the body may not be formed adequately. Such people must receive hormone supplements to maintain a balance in the body.

It has been observed that Octreotide, Lanreotide, Cabergoline, and Bromocryptine are examples of medicines that can shrink the Pituitary tumor, apart from suppressing the production of excess hormones.

Interventional treatment including surgery and indications for surgery/surgical treatment

Surgery is performed when:

• The tumor produces excess hormones
• The tumor has grown so big that it is compressing the nerves in the brain

Two major approaches for Pituitary surgery are:

• Endoscopic Transnasal Transsphenoidal surgery: This involves the removal of the tumor by passing special instruments through the nose and the nasal sinuses. This avoids a scar on the head. However, when the tumor is too big or when the tumor has spread to nearby nerves and tissues of the brain, this route might not be possible.
• Transcranial approach: The tumors that cannot be removed through the endoscopic method can be removed through this Transcranial route. This involves giving a small cut on the scalp and opening the skull.

Radiation

Radiotherapy is indicated when:

• Surgery is not completely successful in removing the tumor
• Surgery cannot be performed
• A tumor that has previously been cured reappears
• Medication has failed to shrink the tumor

There are several approaches to delivering radiation to the tumor:

• Stereotactic radiosurgery: The rumor is first pin-pointed with the help of a head frame fixed to the skull and using scans. The head frame helps to create a reference point for locating the tumor. Multiple beams of radiation are directed towards the tumor from multiple directions such that they all focus exactly at the tumor. A single sitting is enough to deliver the entire radiation dose through this method.
• External beam radiation: This involves delivering radiation from an external source to the tumor. The radiation has to be given in gradually increasing doses, in multiple sessions, over several weeks. This method carries the risk of damage to nearby tissues.
• Intensity-modulated radiation therapy (IMRT): A doctor can mold the shape and intensity of the radiation beams to surround the tumor through this technique. This also ensures lesser damage to nearby tissue.
• Proton beam therapy: This employs a different kind of radiation called Proton Beams. These beams can be carefully modulated to suit the tumor. However, the high expertise it demands and the advanced technology it requires have limited its usage in most hospitals.

Role of Diet/Exercise/Lifestyle changes/Preventive measures

A strategy called ‘Watchful Waiting’ is employed when the tumor has not yet grown big and hence is not causing any symptoms. This is particularly considered in younger individuals who are leading a normal life despite the pituitary tumor.

Complications

The possible complications are:

• Permanent changes in the hormone level: An untreated pituitary tumor or a tumor that has been successfully removed can result in the absence of hormone production forever. This has to be then balanced by prescribing hormone supplements to the person.
• Disturbances in the vision: When left untreated, a pituitary tumor can press on to the nerves concerned with vision and cause serious problems.
• Pituitary Apoplexy: This is an uncommon yet highly dangerous condition. There is sudden bleeding into the pituitary gland, which results in a sudden unbearable headache and life-threatening consequences.

Prognosis

The long-term outcome of treatment in Pituitary tumors depends on several factors:

• Tumors that are very big, i.e., larger than 1 cm, are found to have a poor outcome. This is because such big tumors tend to invade nearby nerves and brain tissue.
• Pituitary tumors that produce hormones are associated with a relatively poor outcome. This is mainly because of the adverse effects of the excess hormones they produce.
• People with poor overall health tend to have less encouraging results. This includes people with diabetes, heart disease, high blood pressure, lung diseases, etc.

When to contact the doctor/how to identify the complications?

When a person notices any symptoms suggestive of a pituitary tumor, a medical consultation has to be made at the earliest. When there is a family history of conditions like a pituitary tumor or genetic conditions like multiple endocrine neoplasias (MEN), there should be a higher level of caution.

Indications for hospitalization if required

Hospitalization is needed only when surgery is required for the management of pituitary tumors.

Suggested clinical specialists/departments to consult for this condition

• Endocrinology
• Oncology