Paediatric Craniopharyngioma

Introduction 

Having your child diagnosed with a paediatric craniopharyngioma (PCP) can be very daunting, especially if you are not quite sure exactly what it is. A PCP is a benign tumour which can be found in the brain. 

PCPs are extremely rare and they occur near a structure known as the pituitary gland which is attached to the brain and controls many hormones. Whilst it is mostly benign, PCPs are located around a very important part of the brain and removing it, while at the same time leaving the brain unharmed, might be a bit tricky. 

Diagnosing this tumour at an early stage is important because it can begin to grow and exert pressure on nearby parts of the brain. Children's brains are still growing and developing and this tumour should ideally be removed before it can cause significant harm. 

Understanding PCPs

Our bodies are controlled by the central nervous system (CNS). The CNS consists of the brain and the spinal cord and is responsible for controlling essential bodily processes such as breathing, movement, maintaining our heartbeat, speaking, and more. The brain is especially important in children because it is still growing and developing. When something hinders that growth, such as a tumour, it can have a great impact on a child's development. 

A tumour is an abnormal growth of tissue and PCPs are located near a gland known as the pituitary gland. This gland is located near the base of your brain and it is attached to it by a “stalk-like” piece of tissue. It is a very important gland which is responsible for producing, storing, and secreting hormones. A tumour can be benign or malignant and PCPs are mostly benign which means they are not cancerous.¹

Aetiology and risk factors

PCPs are rare in children under two years of age and are most commonly diagnosed between the ages of five to fourteen. PCPs are overall extremely rare with only 0.5 to 2 cases per million per year. Generally, there are no known risk factors for these tumours and they are seen equally across all genders, races, and geographical locations.¹ It has been proposed that PCP occurs due to a mutation in the CTNNB1 gene, which provides instructions for beta-catenin protein production. The mutation causes too much of the protein to be made, thus provoking tumour growth.¹

PCPs are usually benign (not known to spread to other parts of the body) and they have an excellent survival rate (83% to 96% five-year rate).¹ However, they have a very high rate of recurrence, which means they have a tendency to grow back.¹ There are some factors that increase the risk for recurrence and these can include:²

• A younger age at diagnosis 
• A large tumour size, located in a difficult-to-access position 
• Tight adherence of the tumour to surrounding structures
• If the tumour was incompletely removed and did not receive radiotherapy 

Clinical presentation

PCPs are generally slow-growing tumours but when they grow, they can cause an increase in pressure in the skull which is known as raised intracranial pressure. They can also exert pressure on various parts of the brain in relation to their position, which can cause symptoms such as:¹ 

• Headaches- a very common symptom and they usually occur in the mornings and go away after vomiting 
• Nausea and vomiting 
• Visual disturbances- also a common symptom and unfortunately, they are difficult for children to express so there is a risk of it leading to permanent visual loss 
• Hearing loss 
• Problems with balance and walking 
• Increased size of the head- usually more common in younger children 
• Increased thirst and frequent urination
• Fatigue or decreased energy levels 
• Personality changes or hallucinations 
• Short height and slow growth 
• Obesity 
• Delayed puberty

It is not necessary that your child exhibits all of these symptoms. There are other medical conditions which exhibit similar symptoms and hence, it is important to contact a healthcare professional in order to obtain a proper diagnosis. 

Some of these symptoms are caused by the physically growing tumour and some are caused by hormonal disturbances.³ 

Diagnostic evaluation 

The first step to a diagnosis is taking a detailed medical history and doing a physical exam. This exam will also include a neurological examination during which your child's movements, coordination, reflexes, and muscle strength will be tested. Generally, children who have a PCP will present as short in stature and overweight with delayed puberty. Other exams which might be conducted to diagnose the tumour can include the following:¹

Visual testing

A visual test is done to check for visual problems. Your child’s central and peripheral vision will be tested and any disturbances suggest that the tumour has encroached on the parts of the brain which are responsible for controlling vision.

Blood testing

Blood tests include tests to check the levels of various hormones such as adrenocorticotropic hormone (ACTH) or Thyroid Stimulating Hormone (TSH).

Imaging

Imaging tests may include computed tomography (CT) or magnetic resonance imaging (MRI). Usually, MRIs are preferred for diagnosing PCPs as they provide a more detailed picture of the tumour and its relation to surrounding structures.

On imaging, PCPs will appear to have both solid and cystic components. The solid parts will be lined by columnar cells which typically look like a “picket fence”. The cystic parts will appear to be cysts that are filled with a yellow-ish, cholesterol-rich fluid. These features will help the healthcare provider properly diagnose a PCP.

Treatment modalities 

A PCP can be tricky to treat due to its position in the delicate, growing brain. There is no gold standard for treatment but each case is taken on an individual basis. Some things to consider before treatment are the size and location of the tumour and the child's age. 

Surgery

Surgery might be needed if the diagnosis needs to be confirmed, if the tumour is invading surrounding structures and causing neurological symptoms, or if hydrocephalus (build-up of excess fluid in the brain) is present.¹

Removal of all of the tumours might not be appropriate at times due to the increased risk of various neurological deficits after surgery. Removing the entire tumour does not decrease the rate of recurrence. 

There are generally two types of surgical approaches for PCPs:

• The first is to access the tumour through the nose using a thin tube with a camera, known as an endoscope. This procedure is known as endoscopic endonasal transsphenoidal surgery (EET) and it is minimally invasive and negates the need for the traditional open type of surgery⁴
• The second is the traditional open surgery known as the transcranial approach during which the tumour is approached directly through the skull

Deciding which surgery is best for your child depends on the size and location of the tumour. ETT should be avoided with larger tumours or if the tumour has invaded the blood vessels. 

Radiotherapy

Radiation therapy is usually done in combination with surgery and it uses high-energy waves to destroy the tumour cells. It can improve the outcomes but it does not prevent recurrence. Radiotherapy can be given externally from outside the body or internally through carefully sealed ”seeds”.¹ 

Internal radiotherapy can be given near or even directly into the tumour.⁵ Care needs to be taken during radiotherapy in order to minimise side effects and to avoid damaging important parts of the brain that can affect a child's growth or development. Radiotherapy also needs to be given in such a way that it avoids damaging surrounding organs. 

Cyst drainage

If the tumours consist of a lot of cysts, a small catheter can be placed in the brain to drain the cysts. Medication might also be administered after drainage to prevent or delay the cyst from producing more fluid. This procedure can relieve some symptoms by lowering the pressure in the brain.¹ 

Chemotherapy and immunotherapy

Chemotherapy is typically a systemic treatment that uses anticancer drugs to destroy tumour cells. It can be given directly into the cysts for some PCPs.⁶

Immunotherapy is a treatment that helps your immune system to fight cancer cells. The drug used for this kind of therapy in PCPs is called interferon alpha and it is given through a vein (intravenously) or directly into the tumour with the help of a catheter. 

Hormonal therapy

It is also important to check the levels of hormones circulating in the body and administer hormonal treatments for any deficiencies. Frequently, growth hormone will be needed after any treatment is given. Treatments for other deficiencies are based on blood levels of the specific hormone.¹

Summary 

PCPs are very rare and are usually diagnosed after early childhood. These benign tumours grow near the pituitary gland in the brain. They are slow-growing and do not spread to other parts of the body but they do have a high rate of recurrence. 

Treating PCPs can be a little tricky due to their position in the brain but they must be removed before they increase in size, exert more pressure on the brain, and cause further neurological symptoms. They can be treated through surgery, radiation, or a number of other ways and your doctor will decide the best approach for your child. 

Generally, PCPs have a very good mortality rate but you might need regular checkups after treatment. You must also keep an eye on any new symptoms so that any recurring tumours can be quickly diagnosed.