Tumours of the Pituitary Gland and Skull Base

The pituitary gland is a small but vital part of the body. About the size of a pea, it sits at the base of the brain, off the hypothalamus, in a bony cavity called the sella turcica. It also happens to be just behind the bridge of the nose in close proximity to the optic nerves. It produces hormones that regulate various organs and glands, making it critical to the functioning of the body. It controls the thyroid, adrenal glands, overies, testicles and so on and hence is also known as the ‘master gland.’

Pituitary tumors are among the most common intracranial tumours occuring in a variety of sizes from small, hormonally-active microadenomas to the larger, non-secretory macroadenomas. Most of them (more than 90%) are benign tumours which are slow growing. About 5 to 10% are a little more aggressive and less than 1% are malignant pituitary carcinomas.

As the numbers indicate, a lot of these tumours are small and don’t have any noticeable symptoms, thereby leaving normal life largely unaffected. In fact, nearly 20% of people have pituitary tumours but many go through their whole lives without having them diagnosed. Those which do grow though can have serious effects considering the critical nature of the pituitary’s functions.

They require surgery without delay!

Traditionally, surgery to this part of the brain and to the base of the skull was extremely challenging. Accessing the tumours because of the location was so difficult that success rates were very low. All that has changed thanks to modern technology and medicine and today surgeons enjoy a very high degree of success in treating pituitary tumours through the endoscopic endonasal approach. In fact, today most such tumours are accessed and excised using this approach.

A surgeon uses the Transnasal Endoscopic Approach to reach a pituitary tumor

Acromegaly occurs when high levels of growth hormone make bone and soft tissue grow excessively. It is usually caused by a tumour in the pituitary gland. Symptoms of acromegaly may include:

• Large growth in the hands and feet (rings or shoes may no longer fit)

• Severe acne

• Thickening of the skin

• Deepening of voice

• Protrusion of forehead and jaw

• Excessive sweating

• Fatigue

Complications can include the following

• Sleep apnea

• Diabetes

• High blood pressure

• Heart disease

• Irregular menstrual cycles in women

• Erectile dysfunction in men

The preferred surgical treatment for it is the Endoscopic Endonasal Approach (EEA)

Also referred to as juvenile nasopharyngeal angiofibroma (JNA), angiofibroma is a benign (noncancerous) tumour of the nasal cavity. Adolescent boys are almost exclusively affected by this, typically between the ages of 10 and 19, though they may affect boys as young as 7. Although benign, it can act in a malignant fashion by eroding into the surrounding sinuses, orbit or cranial vault. Common symptoms of angiofibroma include:

• Nasal obstruction

• Nose bleeding (epistaxis)

• Runny nose (rhinorrhea)

Some patients can develop facial deformities or abnormalities like

• Swelling of the cheek

• Drooping eyelids

Tumours of the Pituitary Gland and Skull Base

• Bulging eyes

• Cranial nerve palsies

Complications

• An obstruction of the eustachian tube might result in hearing loss

• Pressure on the optic nerve and chiasm can result in double vision or blindness

• Occasionally patients may lose their sense of smell (anosmia)

The preferred surgical treatment for angiofibroma is the Endoscopic Endonasal Approach (EEA)

Usually located in the skull, and rarely in the spinal cord, arachnoid cysts can grow to a large size due to the retention of cerebrospinal fluid. Three different membranes called ‘meninges’ comprise the protective covering enveloping the central nervous system. They are:

• Dura mater

• Arachnoid mater

• Pia mater

Cerebrospinal fluid is mainly contained between the arachnoid layer and pia mater. An arachnoid cyst may form when layers of the arachnoid membrane split apart and become filled with cerebrospinal fluid.

In extreme cases, cysts have been known to cause a change in the shape of the head or displace surrounding lobes of the brain.

Symptoms
Symptoms depend on the size and location of the cyst. Tiny cysts may cause no symptoms at all and can be discovered during an unrelated exam. Larger cysts may cause a number of neurologic symptoms such as

• Headache

• Nausea and vomiting

• Seizures

• Hearing and visual disturbances

• Balance problems

• Hydrocephalus (enlargement of the head due to accumulation of cerebrospinal fluid)

The preferred surgical treatment for certain arachnoid cysts of the skull base is the Endoscopic Endonasal Approach (EEA).

Chordomas are rare, slow-growing tumours which develop from the remnants of notochord (which precedes the spinal column during embryonic development). Chordomas account for just 1% of central nervous system cancers and are usually found in adults between 40 and 70. While chordomas can occur at any site along the axial skeleton, they are most often found at the base of the spine (sacrum), tailbone (coccyx) and base of the skull (clivus). Chordomas rarely spread (metastasize) but are aggressive locally., affecting adjacent organs, tissue and bone. Symptoms of chordomas may include back pain, numbness, headaches and problems with vision. Treatment for chordomas vary and can include surgery (via the Endoscopic Endonasal Approach), chemotherapy and radiation.

Craniopharyngiomas of the skull base are benign (noncancerous) tumors that grow in the area of the pituitary gland and are most often found in children. In fact, nearly half of all craniopharyngiomas develop in people below 20. The preferred surgical treatment for craniopharyngiomas of the skull base is the Endoscopic Endonasal Approach (EEA).

Cushing’s disease is a condition caused by chronic exposure to elevated levels of the hormone cortisol (hypercortisolism) due to a pituitary tumour.

Symptoms

• Weight gain on the upper body and trunk

• Moon-shaped face

• Changes in skin (darkening, purple stretch marks, acne and/or easy bruising)

• Excess hair growth and menstrual disorders (in women)

• Decreased fertility and libido

• High blood pressure

• Water retention or swelling

• High blood sugar or diabetes

• Tiredness or fatigue

• Personality changes or mood swings

• Muscle weakness

• Osteoporosis

The preferred surgical treatment is to remove the pituitary tumour causing Cushing’s disease using the Endoscopic Endonasal Approach (EEA)

There are 2 primary types of invasive fungal sinus infections – acute and chronic. The acute version is more serious and mostly occurs in people with compromised immune systems. While fungi usually feed on dead organic matter, weakened immune systems allow fungi to begin eating live tissue. As the fungus reproduces, it spreads into blood vessels, the eye region and central nervous system with lethal effect. Acute invasive fungal sinusitis is a rare condition with a high mortality rate.

Fungal infection of the sinuses might occur when fungal organisms are inhaled and deposited in nasal passageways and paranasal sinuses. This causes inflammation. The dark, moist environment of the sinuses is ideal for fungi to reproduce without light or food. Most fungal infections of the sinuses are non-invasive i.e. they won’t spread to surrounding tissue.

While symptoms are similar to a sinus infection (congestion, facial pain, swelling and discharge), patients may be severely ill.

Symptoms of chronic invasive fungal sinusitis
Patients with chronic invasive fungal sinusitis may have symptoms of a long-standing sinus infection such as congestion, drainage and pressure in the forehead, nose, and behind the eyes. The preferred surgical treatment for invasive fungal sinusitis is the Endoscopic Endonasal Approach (EEA).

A tumor of the protective linings of the brain and spinal cord (called meninges) is called a meningioma. While most meningiomas are benign, some can be malignant. Benign meningiomas grow slowly and usually don’t cause problems unless pressing on the brainstem or compressing structures like the optic and cranial nerves. Malignant meningiomas grow faster and often causing neurological problems and possible swelling in the brain. Symptoms may include:

• Headaches

• Vomiting

• Double or blurry vision

• Changes of behavior

• Seizures

• Loss of sensation or weakness in the arms and legs

• Slurred speech (if the tumour is on the left side of the brain)

• Loss of coordination and memory loss (if tumour is in the temporal lobe)

• Difficulty in writing (if the tumour is in the parietal lobe)

Treatments for meningiomas vary depending on type and location.

The nasopharynx is located behind the nose and above the back of the throat. On each side of the nasopharynx are the Eustachian tubes which connect to the ears. Nasopharyngeal cancer typically arises in the thin lining of the nasopharynx in the space behind the Eustachian tubes. It is more common in Southern China and most often found in men.

Symptoms
Since the tumour grows within air-filled spaces, it may not exhibit symptoms until it is large enough to block passage of air or smell or vision. They include:

• A lump in the neck caused by a swollen lymph node

• A sensation of fullness or pressure in the ear

• Popping noises, hearing loss, and ear infection

• Nasal regurgitation of food and liquids

• Impaired (hypernasal) speech

Tumours of the Pituitary Gland and Skull Base

• Headaches

In advanced cases, infiltration of NPC into the spine can cause

• Stiff neck

• Pain

• Neck instability

The preferred surgical treatment for NPC is the Endoscopic Endonasal Approach ODONTOID PANNUS (Rheumatoid Pannus, Odontoid Synovial Cyst) Odontoid pannus is abnormal tissue that grows in the region of the odontoid process – a toothlike projection at the back of the second cervical vertebra which serves as the pivot for the turning of the head.

This membrane of granulated tissue forms most often as a result of rheumatoid arthritis, in which the condition is called a rheumatoid pannus. Odontoid pannus may also develop due to severe trauma to the neck at the second cervical vertebra.

A similar (although rarely diagnosed) condition which has similar symptoms and treatment is the odontoid synovial cyst.

Rheumatoid pannus
Rheumatoid arthritis (RA) is a progressive auto-immune disease that causes chronic inflammation of the joints. When it attacks, it usually begins in the synovium – a kind of tissue that lines the joint capsule. Cells in the synovium begin to grow and divide abnormally (synovitis) causing a thickening of the synovium resulting in an inflamed and swollen joint.

As it progresses, the synovium can grow larger and form an inflamed, granulated sheet of tissue called rheumatoid pannus. This tissue will spread from the synovial membrane, causing considerable destruction as it invades the subchondral bone.

Symptoms of cervical–spinal abnormalities develop in approximately 60% to 80% of patients with rheumatoid arthritis. When RA invades the cervical spine, the resulting extension of pannus into the spinal canal may compress the brain stem, spinal cord and vertebral arteries causing severe pain and disability.

Left untreated rheumatoid pannus can even result in sudden death.

Treatment
An instability of the joints results in progressive deformity. Generally, in order to stabilise the joints, cranio-cervical fusion is recommended.

If the patient suffers from compression of the spinal cord or brainstem, surgery to decompress them is recommended. In these cases, the Endoscopic Endonasal Approach is best.

Sometimes a tumour or bony structure may compress the optic nerve thereby affecting its performance. In the course of time, it can even lead to the ‘death’ of the optic nerve, a condition also called optic neuropathy. The most common symptom of this is a gradual loss of vision. Treatment for this would be decompression of the optic nerve using the Endoscopic Endonasal Approach (EEA).

This is a chronic condition wherein there is an inflammatory reaction in the orbital tissues surrounding the eyes, which behaves a lot like a brain tumour. Since it is not a tumour, it does not spread or invade adjacent or nearby tissue but, it can compress surrounding structures. Orbital inflammatory pseudotumors might resolve with steroid treatment or on their own.

Pituitary apoplexy occurs when a pituitary adenoma either spontaneously hemorrhages or grows in such a way as to compress and cut off its own blood supply, resulting in the death of tumour cells, bleeding and acute swelling. The haemorrhage or necrosis-induced swelling can compress the

• Pituitary gland

• Optic nerves

• Nerves that control eye movement

Possible symptoms

• Severe headache

• Nausea

• Vomiting

• Visual loss/double vision

• Loss of consciousness

• Fever

• Stiff neck

• Hormone insufficiency

Pituitary apoplexy is a medical emergency which can be fatal if left untreated. However, with treatment the prognosis is good.

The preferred surgical treatment for pituitary apoplexy is the Endoscopic Endonasal Approach to remove the tumor and decompress the area. Surgery is performed after medical stabilisation.

Click here to read about how surgeons at Sita Bhateja Speciality Hospital saved Nagaraj from pituitary apoplexy.

A Rathke cleft cyst is a rare type of cyst believed to originate from remnants of the Rathke pouch. During embryonic development, Rathke’s pouch forms as a depression in the roof of the mouth, eventually losing its connection to the pharynx and giving rise to the anterior pituitary gland. If instead of regressing the cleft persists and enlarges, it may form into a cyst. Most of these cysts are:

• Very small (less than 2 mm)

• Cause no symptoms

• Discovered incidentally from imaging studies for other conditions

In some instances, continual accumulation of fluid may cause the cyst to grow. As it grows it places pressure on surrounding structures, including:

• Pituitary gland

• Optic chiasm

• Hypothalamus

This pressure results in associated symptoms.

Rathke cleft cysts are very similar in presentation and origin to craniopharyngiomas. The difference is that craniopharyngiomas grow by cell division and fluid accumulation, whereas Rathke cleft cysts grow only by fluid accumulation.

The preferred surgical treatment for Rathke cleft cyst is the Endoscopic Endonasal Approach (EEA).