pituitary tumor



Overview

What is a pituitary tumor?

Definition of Pituitary Tumor

Pituitary tumors are a group of tumors that originate from the pituitary gland and are common intracranial tumors.

The pituitary gland is located in the central part of the base of the brain and is divided into the adenopituitary gland (anterior pituitary gland) and the neuropituitary gland (posterior pituitary gland), which are the most important endocrine glands in the body and regulate the secretion of hormones.

Pituitary tumors are derived from the adenopituitary gland, the neuropituitary gland, and the squamous epithelial remnants of the embryonic craniopharyngeal bursa, with adenopituitary tumors accounting for the majority of these tumors.

Types

Functional typing

According to whether the tumor cells have the function of synthesizing and secreting hormones.

Functional pituitary tumor

Tumor cells synthesize and secrete hormones.

Commonly known as prolactinomas, other types include growth hormone tumors, adrenocorticotropic hormone tumors, thyroid hormone tumors, luteinizing hormone/follicle stimulating hormone tumors, and mixed tumors.

Non-functioning Pituitary Tumors

Tumor cells that do not synthesize or secrete hormones are common in the elderly population.

When the tumor is large in size, it may compress the pituitary gland or brain tissue and cause corresponding symptoms, such as visual impairment and hypopituitarism.

Classification according to the size of pituitary tumor

Microadenoma: tumor diameter <10 mm.

Macroadenoma: tumor diameter ≥10 mm.

Morbidity

Pituitary tumor is the most common intracranial tumor, accounting for 15% of all intracranial tumors.

There is no authoritative data in China, and foreign surveys show that the prevalence of this disease is about 77/100,000 people.

Pituitary tumors can occur at any age, with males slightly more than females.

Questions you may be concerned about

Is pituitary tumor a cancer?

Pituitary tumors, unlike pituitary cancer, are benign tumors.

Pituitary tumors are tumors originating from the adenopituitary gland, the neuropituitary gland, and the remnant squamous epithelium of the embryonic craniopharyngeal bursa, with adenopituitary tumors accounting for the majority of these tumors. Almost all pituitary tumors are benign, and most of them can be controlled by surgery and medication without affecting life and work.

Pituitary carcinoma refers to pituitary tumors accompanied by subarachnoid space, brain tissue or systemic metastasis, accounting for only 0.4% of all pituitary tumors, with a poor prognosis.

Are pituitary tumors and pituitary adenomas the same?

Pituitary adenomas are the most common type of pituitary tumor.

The pituitary gland is divided into adenopituitary and neuropituitary, and the sources of pituitary tumors include the adenopituitary gland, the neuropituitary gland, and the squamous epithelial remnants of the craniopharyngiocyst in the embryonic stage.

Pituitary adenomas account for the majority of pituitary tumors and are usually benign.

The main manifestation of pituitary tumor is that the pituitary gland secretes too much or not enough hormones, and headache, vision loss, visual field defect, urolithiasis and so on.

Who is susceptible to pituitary tumors?

Pituitary tumors are the most common intracranial tumors.

Pituitary tumors are seen in people of all ages, slightly more in men than women, and the incidence of pituitary tumors increases with age.

The pathogenesis of pituitary tumors is unclear and may be related to genetic, endocrine function abnormalities, and environmental factors. Therefore, people with a family history of pituitary tumors, radiation therapy, and abnormalities of the hypothalamus and thyroid, gonads, and adrenal glands may have a higher risk of developing pituitary tumors.

Causes

Causes

Genetic factors

May be associated with gene mutations that lead to proliferation of abnormal pituitary cells.

About 5% of pituitary tumors are familial, such as multiple endocrine adenomatosis type 1 and familial growth hormone tumors.

Hypothalamic factors

Increased secretion of hormones in the hypothalamus, such as growth hormone-releasing hormone and adrenocorticotropic hormone-releasing hormone.

Environmental factors

Such as receiving radiation therapy, etc.

Target glands of pituitary hormone-releasing hormone

Failure of target glands of pituitary hormone-releasing hormones, such as thyroid, gonads, adrenal glands, etc.

Pathogenesis

Some scholars believe that pituitary tumors are caused by a mutation in a pituitary cell, resulting in the activation of oncogenes (genes that cause abnormal cell proliferation) and/or the inactivation of oncogenes (genes that prevent abnormal cell proliferation).

The mutated cells proliferate under the influence of internal and external factors, and gradually develop into pituitary tumors.

Symptoms

Early clinical manifestations of pituitary tumors (especially microscopic adenomas) are rare.

Typical symptoms

Tumor localization and local compression

Headache

Mostly caused by the tumor pulling the meninges.

It is mainly a vague pain or swelling pain with paroxysmal severe pain in the forehead and both temporal sides.

Visual impairment

Pituitary tumor compresses one or both optic nerves, causing optic nerve atrophy, vision loss and partial blindness.

Other symptoms

Compression of cavernous sinus: causing cavernous sinus syndrome, there may be congestion and edema around the eyes, protruding eyeballs, motor paralysis, pupil dilation, loss of reaction to light, numbness or pain in the eyes and frontal region, accompanied by chills and fever.

Compression of the olfactory nerve: causing damage to the olfactory nerve may result in loss of sense of smell.

Invasion into the hypothalamus: symptoms such as urolithiasis (with excessive drinking, polyuria, irritable thirst, etc.), lethargy, and thermoregulatory disorders may occur.

The tumor occasionally extends to other parts of the brain, causing epileptiform convulsions and hemiparesis.

Pituitary giant adenoma may present with headache, nausea, vomiting and increased cranial pressure.

Hormone secretion abnormality

The secretion of pituitary hormones and the lack of secretion of pituitary hormones are different, and the clinical manifestations are different.

Prolactinoma

Female: menstrual changes and infertility, breast milk overflow, weight gain, bone pain, osteoporosis, hirsutism, seborrhea and acne.

Males: erectile dysfunction, decreased libido, male infertility, hypogonadism (slower beard growth, anterior hairline, thinning of pubic hair, softening of testicles, etc.).

Growth hormone tumor

Epiphyseal closure: Mostly seen in adults, acromegaly can occur, mainly involving the face, hands and feet. There is widening of nose, hypertrophy of lips, enlargement of hands and feet, swelling, stiffness and deformation of joints, thickening of skin and excessive sweating.

Unclosed epiphysis: It is mainly seen in children, and may present with height higher than that of the same age, or even gigantism.

Adrenocorticotropic hormone tumor

Because the tumor secretes adrenocorticotropic hormone, it can cause Cushing’s syndrome.

There are fat accumulation in the upper body and face, “full moon face”, thinning of skin, purple lines, high blood pressure, osteoporosis, sexual dysfunction and so on.

Thyroid-stimulating hormone tumor

The secretion of thyrotropin leads to an increase in thyroid hormones and hyperthyroidism.

Symptoms of hypermetabolism such as pyrexia, excessive sweating, diarrhea, weight loss, palpitations, etc. may be present.

Complications

Loss of vision

Pituitary tumor compressing the optic nerve can lead to vision loss, visual field defects, etc., and even blindness.

Pituitary stroke

Pituitary stroke is most common after a large, fast-growing pituitary tumor, radiotherapy or bromocriptine.

Clinical manifestations include sudden severe headache, high fever, vision loss, visual field defects, nausea, vomiting, confusion, and even death.

Meningitis

There may be high fever, headache, vomiting, impaired consciousness and mental symptoms. The rate of death and disability is high.

Permanent Hormone Deficiency

An enlarged pituitary tumor can lead to pituitary atrophy, which may permanently alter hormone availability with hypothyroidism and hypoadrenocorticism.

Hydrocephalus and increased intracranial pressure

This is usually seen as a result of backward or upward progression of the tumor, causing compression of the third ventricle and the midbrain aqueduct, or due to the occupying effect caused by the large size of the tumor, which may be accompanied by symptoms such as severe vomiting, headache, and so on.

Consultation

Department of Medicine

Neurosurgery

If you have symptoms such as headache, vision loss, acromegaly, excessive drinking, excessive urination, abnormal appetite, amenorrhea, infertility, erectile dysfunction, etc., consult a doctor promptly.

Endocrinology

Patients may also visit the Endocrinology Department for consultation and treatment.

Preparation

Preparing for the consultation: registration, preparation of documents, common problems

Tips for your visit to the doctor

Try to keep a record of the symptoms you have experienced so that you can give more reference to your doctor.

Avoid self-medication before the consultation as it may aggravate the symptoms or cover up the condition.

Preparation Checklist

Is the headache severe? Is the pain persistent or intermittent?

Do you usually have normal menstruation? How long has it been since menopause?

How is your vision? Is there any foreign body sensation in the eye? How is your vision?

Is your sex life normal?

Do you suffer from chronic headaches, cavernous sinus syndrome, etc.?

Is there a family history of pituitary adenoma?

Laboratory tests: serum prolactin, serum growth hormone, serum adrenocorticotropic hormone, gonadotropin, thyroid function tests.

Imaging: Cranial CT, Cranial MRI, PET-CT, SPECT

Other tests: pathologic examination

Bromocriptine, octreotide, pegvisomant, cyproheptadine

Diagnosis

Diagnosis based on

Medical history

There may be a history of chronic headache, a history of amenorrhea in women, and a history of cavernous sinus syndrome.

Clinical manifestations

Presence of headache, changes in vision and visual field, endocrine abnormalities, etc.

Physical examination

To find out whether there is acromegaly, abnormal vision and visual field, and whether there is hypogonadism in males.

Laboratory Tests

The type of pituitary tumor can be determined by testing the level of hormones related to the pituitary gland in the blood.

Serum Prolactin Measurement

Blood is collected in the early morning on an empty stomach.

Normal serum prolactin level is usually less than 20 μg/L. If it is more than 200 μg/L, it is highly suggestive of prolactinoma.

Serum growth hormone measurement

Fasting or random serum growth hormone <2.5 ng/ml is considered normal.

If greater than normal, an oral glucose tolerance test (OGTT) and insulin-like growth factor (IGF-1) are performed to aid in diagnosis.

Serum adrenocorticotropic hormone

Some may have markedly elevated proadrenocorticotropic hormone, with increased plasma cortisol and urinary free cortisol. Diagnosis can be aided by the dexamethasone test and corticotropin-releasing hormone excitatory test.

Gonadotropins

Follicle stimulating hormone or luteinizing hormone is normal or decreased, and testosterone and estradiol need to be measured at the same time to assist in the diagnosis.

Thyroid function tests

Thyroid-stimulating hormone tumor may have elevated plasma levels of thyrotropin (TSH), triiodothyronine (TT3), serum thyroxine (TT4), serum free triiodothyronine (FT3) and serum free thyroxine (FT4).

Imaging

Cranial CT and magnetic resonance imaging

are the most commonly used tests to detect pituitary microadenomas <10 mm in diameter.

They can also provide information on the location, size, and relationship to surrounding tissues and organs for possible surgical management.

Positron emission tomography (PET-CT)

It is used to observe physiological and biochemical processes such as blood flow in pituitary tumors, and can differentiate between tumor necrosis and recurrence during treatment.

Single Photon Emission Computed Tomography (SPECT)

Radiolabeled dopamine receptor agonist imaging is used to differentiate prolactinomas from non-functioning tumors, and radiolabeled growth inhibitory hormone scanning is used to diagnose ectopic adrenocorticotropic hormone syndrome.

Histopathologic examination

Immunocytochemical staining of resected specimens is able to differentiate which hormones are contained in the tumor cells and can clarify the staging.

Differential diagnosis

Craniopharyngioma

Similarities: visual field defects, headache, vomiting and optic disc edema with increased intracranial pressure; urolithiasis, polyphagia or anorexia, fever, obesity; amenorrhea and infertility in females, hair loss and decreased libido in males; precocious puberty, acromegaly, breast milk spillage, etc.

Differences: The X-ray manifestation of craniopharyngioma is the suprasellar type with pterygoid compression and bed protrusion damage; the intrasellar type makes the anterior and posterior diameter of the pterygoid enlarged like pterygoid, and there are often calcified plaques or cystic wall calcification in the form of arcs or eggshells. Magnetic resonance imaging and endocrine examination can be differentiated.

Rathke’s cyst (Rathke’s cyst)

Similarities: Headache, impaired vision and visual fields, urolithiasis and hyperprolactinemia may be present.

Differences: Rathke’s cyst is a round or round-like mass with well-defined borders in the saddle or with suprasellar growths on CT scan; on magnetic resonance imaging the cyst density signal is mostly homogeneous with well-defined borders.

Lymphocytic pituitary inflammation

Similarities: Clinical manifestations may include hypopituitarism and pituitary masses, uremia, headache, and visual field defects.

Differences: Lymphocytic pituitary inflammation is more common in pregnant or postpartum women and can be differentiated by histopathologic examination.

Optic nerve glioma

Similarities: Changes in vision, optic disc edema or atrophy.

Differences: Optic nerve gliomas occur more often in female children, are prominent in one eye, and sometimes a mass can be palpated in the supraorbital region. x-ray shows enlargement of the optic nerve foramen, and the pterygoid saddle may have a J-shape or pelvic enlargement. Magnetic resonance imaging and CT can identify it.

Ectopic pineal tumor

Similarities: There may be visual loss, hemianopsia, uremia or hypopituitarism.

Differences: Ectopic pineal tumors are most common in children and adolescents. They often present with loss of thirst and chronic hypernatremia. There is no abnormality in the pyriform saddle and magnetic resonance imaging can show the tumor. It can be differentiated by CT and MRI.

Internal carotid artery aneurysm

Similarity: partial blindness and hypopituitarism may be present.

Differences: Internal carotid aneurysms can be visualized as a mass at the carotid bifurcation that separates the internal and external carotid arteries and widens the spacing between them. Confirmation of the diagnosis relies on magnetic resonance imaging and angiography.

Retrobulbar optic neuritis

Similarities: Visual disturbances and pupillary reflex deficits may be present.

Differences: Retrobulbar optic neuritis has a rapid onset, and the visual impairment is mostly one-sided, with recovery within a few weeks in most cases. There is no endocrine dysfunction, and imaging shows that the pterygoid is normal.

Meningioma

Similarities: increased intracranial pressure, such as paroxysmal headache, vomiting, optic disc edema; imaging is similar to that of tumors in the pterygoid region.

Differences: The magnetic resonance imaging of meningiomas often shows a “meningeal tail” near the tumor, suggesting that the tumor is attached to the meninges and grows along the meninges.

Vacuolar pterygoid syndrome

Similarities: headaches and visual field defects, as well as pituitary abnormalities. Enlargement of the pterygoid is also seen on imaging.

Differences: CT of vacuolar pterygoid syndrome can show enlarged pituitary fossa, the saddle is filled with low-density cerebrospinal fluid, and the compressed and flattened pituitary gland is crescent-shaped located in the posterior and inferior part of the saddle fossa or disappeared, which forms the characteristic “funnel sign”; the function of adeno-pituitary gland is normal, and pituitary hormones can not be detected in the cerebrospinal fluid.

Treatment

Principles of treatment

If the tumor causes local compression, it is necessary to remove the tumor tissue or inhibit the growth of the tumor.

The tumor autonomously secretes a large amount of hormones, which needs to be corrected to alleviate the clinical manifestations.

Restore and preserve the intrinsic function of the pituitary gland as much as possible.

Prevent tumor recurrence, or recurrence at the clinical and biochemical levels.

To minimize local and systemic complications associated with treatment.

Note: All medication should be used under the guidance of a specialized physician, and should not be adjusted in dosage or discontinued on its own.

Medication

Dopamine agonists

Commonly used drugs: Bromocriptine.

Indications: Commonly used for people with pituitary tumors with hyperprolactinemia. It can reduce prolactin level and shrink the pituitary tumor.

Dosage: When taking the drug, it should be taken from a small dose and gradually increased, and the specific dose should be carried out according to the doctor’s instructions.

Adverse reactions: related to the size of the dosage, and there are great individual differences, after reducing the dose or stopping the drug, all the reactions can disappear. Therefore, after using the drug, close observation should be made and the dosage should be adjusted at any time.

Precautions: Use the drug as prescribed by the doctor, avoid discontinuing the drug on your own, the symptoms may recur after discontinuing the drug, and the tumor may increase in size.

Growth inhibitor analogs

Commonly used drugs: Octreotide.

Effects: Can inhibit growth hormone, thyrotropin, etc..

Indications: Commonly used for acromegaly due to pituitary tumor.

Adverse effects: There may be pain or pins and needles sensation at the injection site, which may be relieved after 15 minutes. There may also be gastrointestinal adverse reactions, such as anorexia, nausea, vomiting, diarrhea, abdominal cramping pain.

Growth hormone receptor antagonists

Commonly used drugs: pegvisomant.

Effects: Decrease the concentration of insulin-like growth factor-1 (IGF-1) in patients with acromegaly, which can normalize the low level of serum total cholesterol (TC), low-density lipoprotein (LDL), lipoprotein B and high lipoprotein A.

Precautions: Liver function should be monitored periodically during administration.

Serotonin receptor inhibitors

Commonly used drugs: cyproheptadine.

Adverse reactions: there may be drowsiness, dry mouth, fatigue, dizziness, nausea and other adverse reactions.

Precautions: If the adverse reaction is large, the drug should be stopped immediately and medical attention should be sought.

Surgical treatment

Drug treatment is preferred for prolactinoma, and the treatment of choice for other pituitary tumors is surgery, especially in the presence of pituitary stroke which must be treated immediately or as soon as possible.

Transnasal and pterygoid sinus pituitary tumor resection

This is the treatment of choice for pituitary tumors and allows complete removal of the tumor.

Advantages

It does not require craniotomy, has less surgical damage, preserves the function of the pituitary gland, has fewer postoperative complications, and has a satisfactory outcome.

Indications

Pituitary microadenomas that are mildly protruding to the saddle or confined to the saddle.

Efficacy

The cure rate after resection of microadenomas can reach more than 90%.

The cure rate of macroadenoma surgery can reach 50%.

Complications

Uremia, cerebrospinal fluid leakage, meningitis, hypopituitarism, impaired vision, etc.

Craniotomy

Advantages

Clear visualization of the surgical field.

Disadvantages

Higher risk of surgical complications and mortality, more difficult to improve endocrine symptoms.

Indications

Tumors that are clearly growing above and outside the saddle.

Treatment effect

Visual acuity returns to normal or progresses in 62.2% of cases, and visual field returns or progresses in 58.3% of cases.

Radiation therapy (radiotherapy)

It is mainly used as an adjunctive treatment to drugs and surgery, including conventional radiation therapy, heavy particle radiation therapy and stereotactic radiation neurosurgery (Gamma Knife).

Indications of radiotherapy

Tumor residue after surgery is relatively large and cannot be effectively controlled by drugs.

Tumor recurrence after surgery.

Suprasaddle lesions that refuse to undergo surgery via the frontal approach.

Radiotherapy is also indicated for those who have locally negative imaging but have obvious biochemical changes and clinical symptoms.

Efficacy

Tumor growth or recurrence can be controlled, but hormone levels return to normal more slowly.

Complications

Hypopituitarism, secondary brain tumors, cerebrovascular disease, visual impairment or radiotemporal lobe necrosis, memory loss, and impact on fertility.

Prognosis

Cure

Most pituitary tumors are benign tumors, which can be controlled by medication or surgery, and can obtain the same life expectancy as normal people.

Most of the prolactinomas can be controlled by medication, and macroadenomas can be seen to shrink after 4-6 weeks or several months of treatment. 25% of patients can be maintained normal after stopping medication, but need to be rechecked regularly.

The cure rate of growth hormone microadenomas can reach 90% after surgical resection, with fewer sequelae.

Hazards

Pituitary tumor is an intracranial tumor, untreated can compress the surrounding tissues, leading to abnormal hormone secretion, and even the crisis of what pituitary stroke.

Hormone secretion abnormality

Growth hormone: excessive secretion of growth hormone in adults will cause acromegaly, and children will develop gigantism, which will affect their appearance and cause low self-esteem, depression and other emotions.

Prolactin: It may cause amenorrhea in women, decreased libido and erectile dysfunction (impotence) in men, and even infertility.

Decreased secretion of pituitary hormones may lead to short stature and sexual underdevelopment in children.

Tumor compressing the tissues around the pituitary gland

Tumor pressure on the optic nerve can cause vision loss, visual field defects and fundus changes, and even blindness.

Tumor growth affecting the hypothalamus may lead to uremia, sleep abnormalities, precocious puberty and hypogonadism.

Tumor enlargement compressing pituitary tissue other than the tumor can lead to pituitary atrophy, hypogonadism, hypothyroidism, hypoadrenocorticism, etc., requiring lifelong hormone replacement therapy.

Pituitary Stroke

Rupture of the pituitary tumor leads to sudden hemorrhage, ischemia, infarction, and necrosis of the pituitary gland and causes sudden pars plana compression and intracranial hypertension, which may be life-threatening.

Daily

Daily life

Diet

Eat a light diet and avoid foods high in salt, sugar and fat such as salty dishes, desserts and fatty meats.

Eat more high-protein foods, such as eggs and soy products.

Take in vitamin-rich foods such as oranges and kiwis as well as iron-rich foods such as animal liver and animal blood to strengthen the body’s immunity.

Exercise

Non-functional pituitary microadenomas do not have special requirements for daily activities, and moderate exercise can be done to improve resistance.

Before the macroadenoma is treated, avoid strenuous exercise; after treatment, start with low-intensity exercise such as walking, and gradually transition to normal.

If the pituitary tumor secretes thyroid-stimulating hormone and causes hyperthyroidism, strenuous exercise also needs to be avoided.

Lifestyle habits

Regular work and rest, avoid staying up late and avoid exertion.

Avoid smoking and drinking alcohol.

Ventilate the room regularly and prevent colds and flu to prevent intracranial infections.

Maintain a positive mindset and learn to regulate bad moods, such as practicing writing and listening to music.

Regular checkups

Regular checkups should be conducted under the guidance of your doctor, and you should pay attention to monitoring your condition and consult your doctor if you feel unwell.

Prevention

There are no effective preventive measures because the cause of the disease is unknown.

A good lifestyle may help in the prevention of pituitary tumors. Try to avoid exposure to harmful environments, such as chemical poisons and radiation.

Pay close attention to your own health and have regular medical checkups for early detection and treatment.