OUR body contains hormones that regulate and control the functions of other organs inside the body.
These hormones are produced and released by the pituitary gland.
This gland is small and pea-shaped in appearance but it plays a major role in regulating vital body functions.
It is also known as the body’s “master gland”.
The organs and hormones that are responsible for the changes inside the body is referred to as the endocrine system.
The pituitary gland is connected directly to the brain and it is located close to the optic nerves, which connects our eyes to the brain.
These optic nerves are responsible for our vision.
A pituitary tumour is an abnormal growth that develops inside the pituitary gland itself.
It is estimated that the prevalence rate of this tumour in the general population is about 17% to 20% and most are benign (non-cancerous) in nature.
The growth can range from a few millimetres to more than 5cm in size.
The clinical presentation of the tumour can be either due to the imbalance of the hormones produced or compression to the nearby structures, especially towards the optic nerves.
A pituitary tumour that is causing a hormonal imbalance in a patient is called a functional pituitary adenoma and it can manifest because of an excessive or inadequate production of hormones.
The type of hormone affected will lead to specific clinical presentations such as acromegaly (from growth hormone), prolactinoma (prolactin hormone) and Cushing disease (excessive corticotropin hormone).
Inadequate production of the hormones would instead cause a condition called hypopituitarism.
The majority of patients who suffer from functional pituitary tumour will note some changes in their external appearance.
These changes depend on the affected hormones such as:
• Enlarged hands and feet
• Frontal bossing (a prominent, protruding forehead)
• Coarseness of facial features
• Accelerated or excessive growth
Cushing disease -
• Exaggerated facial roundness also known as “moon face”
• Fat accumulation on the trunk but fat loss from the arms and legs which is called “central obesity”
• Thinning of the skin with external bruises
When there is no change in the pattern of hormone secretion, the tumour is classified as a non-functional pituitary adenoma. This group of patients is only detected when they are presented with neurological issues such as blurring of vision as there is a significant compression to the surrounding structure, especially the optic nerves. In view of that, a majority of patients with non-functional pituitary tumour often remain undiagnosed as it usually does not cause any significant symptoms until it reaches a certain size.
The usual complaints include:
• Visual deterioration classically described as bitemporal hemianopia
• Most patients will initially seek treatment at an eye clinic
A patient who is suspected of having a pituitary tumour will have to undergo some blood tests in order to determine the level of the hormones.
At the same time, proper visual assessment by an ophthalmologist is important. An imaging of the brain is also mandatory to identify the size and extension of the tumour.
Treatment options depend on the type and size of the pituitary tumour and it involves a team of medical experts including a neurosurgeon, an ear, nose and throat (ENT) surgeon and an endocrinologist.
An oncologist and a paediatrician also play an important role in the management of this patient.
At Hospital Raja Permaisuri Bainun, a dedicated neuro-endocrine clinic manages patients with pituitary tumours.
Based on the clinical, laboratory and imaging findings, patients with pituitary tumours will be required to be managed with medication, surgical intervention and radiation therapy; either alone or in combination.
Medical treatment can sometimes help to stabilise the hormones and allow the tumour to shrink, thus making surgery unnecessary.
Patients with prolactinoma, for instance, usually respond well to medical treatment.
They show improvement in visual field abnormalities, resolution of symptoms associated with high prolactin level and visible diminution of the actual mass after specific drugs are administered.
However, not all patients can be managed medically.
Those patients who fail to respond to medication will be diverted to surgical intervention.
Conditions that may require a surgical intervention include:
• Acute rapid onset of visual disturbance
• Pituitary apoplexy
• Failed medical treatment
• Tumour growth despite medication
• Intolerance to the side effects of the drug given
• Unable to normalise the hypersecreting hormones with medication
Compression effect to the surrounding nerves, especially towards the optic nerve usually requires prompt surgical treatment.
Patients can develop permanent blindness if left untreated.
There are two main surgical techniques that are usually performed for treating pituitary tumour:
Endoscopic transnasal transsphenoidal (ETSS) approach
The tumour can be reached and removed through the nose and sinuses without an external incision.
No other part of the brain is often affected and there is no visible scar.
Other advantages include shorter operation time and a reduction in the number days in the hospital.
This is the current usual approach at most centres, including Hospital Raja Permaisuri Bainun, Ipoh.
A combination team with the ENT surgeon is used during the procedure. However, a very large tumour may be difficult to remove with this procedure, especially if a tumour has invaded nearby nerves or brain tissue.
Transcranial approach (craniotomy)
During this procedure, the tumour is removed through the upper part of the skull by an incision at the scalp. It is easier to reach large or more complicated tumours using this procedure.
The disadvantages of this approach include longer operation time and it requires brain retraction during the surgery.
Radiation Therapy (RT) is a useful treatment alternative among patients with residual tumours after surgery. It is often necessary for managing local mass effects of large macroadenomas.
Fractionated Stereotactic Radiotherapy (FSR) was found to be safe and effective as it may reduce the possibility of postradiation optic neuropathy.
Post-treatment evaluation is very important for all patients.
Endocrinologic and neuro-ophthalmologic assessment as well as postoperative cerebral imaging study is essential to determine the possibility of residual tumours.