Pineal Region Tumours

What is a pineal region tumour?

Pineal region tumours form in the pineal region of the brain, which is located deep in the centre of the brain in an area called the epithalamus, where the two halves of the brain join. They can form either within the pineal gland itself or in the surrounding area.

An astrocytoma brain tumour develops from brain cells called astrocytes. When astrocytes form an astrocytoma brain tumour, damage can be seen in the DNA and they no longer undergo apoptosis (the cells don’t die when they are supposed to). When this process fails in astrocytes, the cells continue to grow in an uncontrolled way and form into a brain tumour.

What is a pineal gland?

The pineal gland is a small, pinecone shaped gland found deep in the centre of the brain.

The function of the pineal gland is not fully understood, but it is well known for regulating our circadian rhythms. One way that it does this is to produce and regulate melatonin, a hormone that helps to regulate our sleep patterns.

The pineal gland also helps to regulate female hormone balance, and therefore influences female fertility and menstrual cycles.

How common are pineal region tumours?

Signs and symptoms of embryonal tumours depend upon where the tumour has developed.

Common symptoms include:

Headaches
Seizures
Muscular weakness or partial paralysis of facial muscles
Muscular weakness or partial paralysis on one side of the body

As a group, pineal region tumours are diagnosed more often in children than adults, representing 3%-11% of all paediatric brain tumours, compared to less than 1% of brain tumours diagnosed in adults.

What types of brain tumour are classified as pineal region tumours?

Pineal region tumours are grouped into four tumour types, defined in the 2016 report by the World Health Organisation (WHO) entitled “Classification of Tumours of the Central Nervous System (CNS).” However, other tumours found in the pineal region are germ cell in origin and include germinomas, embryonal cell tumours and choriocarcinomas.

All brain tumours are classified based on their characteristics identified by histology (how they look under a microscope), and by molecular profiling (information gained via genetic testing on a sample of the tumour removed during a biopsy).

Pineocytoma

Pineocytomas develop from pinealocyte cells and/or their precursors (the stem and progenitor cells from which pinealocytes form).

Pinealocytes are the main cells in the pineal gland that produce the hormone melatonin.
Classified as WHO grade 1, pineocytomas are relatively easy to remove using neurosurgery due to having a clear boundary where the tumour ends and healthy tissue begins. In such cases, they are considered a benign tumour.
Pineocytomas are often diagnosed when they are less than 3cm diameter.
Pineocytomas account for 14-30% of all pineal region tumours.
Pineocytomas can develop at any age, but occur most often in adults between 20 and 60 years of age.
Pineocytomas are slightly more frequently diagnosed in females than in males.

Pineal parenchymal tumour with intermediate differentiation (PPTID)

Pineal parenchymal tumours with intermediate differentiation (PPTIDs) develop from pinealocyte cells and/or their precursors (the stem and progenitor cells from which pinealocytes form). Pinealocytes are the main cells in the pineal gland that produce the hormone melatonin.
Classified as WHO grade 2 or grade 3, PPTIDs tend to return after treatment and are classified as a low-grade or slow-growing form of cancer.
PPTIDs were only recognised by the World Health Organisation (WHO) as a unique sub-group of pineal region tumours in 2007, so prior to this date tumours now classified as a PPTID may have been called “atypical pineocytomas,” “ malignant pineocytomas” or “mixed pineocytoma–pineoblastomas.”
PPTIDs account for 20-62% of all pineal region tumours.
Although these tumours can be diagnosed at any age, they are most commonly seen in middle age adults (20-70 years of age).
PPTIDs are slightly more frequently diagnosed in females than in males.

Papillary tumour of the pineal region (PTPR)

PTPRs develop from cells called ependymocytes that line the ventricles of the brain and the central canal of the spinal cord, rather than from cells of the pineal gland itself. Ependymocytes are a form of ependymal cell, which is one of the four main types of glial cells. Glial cells give rise to the largest group of brain tumours called gliomas.
Classified as WHO grade 2 or grade 3, PTPRs tend to return after treatment and are classified as a low-grade or slow-growing form of cancer.
Papillary tumours of the pineal region (PTPRs) occur more often in adults than in children, but have been reported in patients ranging from 1 to 70 years, with the average age being around 31 years.
PTPRs occur equally in both males and females.

Pineoblastoma

Pineoblastomas develop from pinealocyte cells and/or their precursors (the stem and progenitor cells from which pinealocytes form). Pinealocytes are the main cells in the pineal gland that produce the hormone melatonin.

Classified as WHO grade 4, pineoblastomas are fast-growing, malignant tumours that tend to invade nearby tissue within the brain and spine, carried in the cerebrospinal fluid (CFS).

There is an association between pineoblastomas and hereditary retinoblastoma, a tumour that forms in the eye. Such patients tend to be diagnosed when they are around 1 year old. This combination of a retinoblastoma and pineoblastoma is called trilateral retinoblastoma.

Pineoblastomas account for 24-50% of pineal region tumours.

Pineoblastomas are most likely to be diagnosed in people under 20 years old.

Pineoblastomas are slightly more likely to be diagnosed in females compared to males.

Treatment options for pineal region tumours

The first line of treatment for pineal region tumours is usually surgery. Luckily, the majority of pineal tumours can be accessed using minimally invasive keyhole surgery that passes over the cerebellum situation at the back and base of the brain.

Surgery is likely to be followed by radiotherapy and chemotherapy.

Discover more about neurosurgery, radiotherapy and chemotherapy here.

New treatments may be available to some patients in the context of clinical trials. These may include immunotherapy, novel combinations of existing chemotherapy drugs, and emerging drugs that target the specific genetic mutations of individual tumour types.

For more information about clinical trials, please click here.

Frequently asked questions

What causes a pineal region tumour?

The precise cause of most pineal region tumours is not yet understood.

However, people living with an inherited genetic disorder called bilateral retinoblastoma are more likely to develop a pineal region tumour called pineoblastoma than people without this condition.

Read more about the causes of brain tumours here.

What are the symptoms of pineal region tumours?

Pineal region tumours originate from deep within the centre of the brain, close to the third ventricle (one of the large fluid filled spaces). This means that patients often experience increased pressure inside the skull due to a build-up of cerebrospinal fluid (CSF), a condition known as hydrocephalus.

Signs and symptoms of pineal region tumours may include:

Headaches
Nausea and vomiting
Unusual eye movements or difficulty controlling the eyes: in particular, a characteristic upward gaze palsy, known as Parinaud syndrome
Poor balance, for example whilst walking
Poor co-ordination (ataxia)
Disruption of sleep patterns
Seizures
Memory issues
Early puberty in children

Read more about symptoms of a brain tumour here.

Are pineal region tumours benign or cancerous?

The degree of malignancy depends upon the grade of the tumour.

A grade 1 pineal tumour that is easily removed would be classed as benign.

A grade 2 or 3 pineal tumour tends to return after treatment and would be classified as a low-grade or slow-growing form of cancer.

A grade 4 pineal tumour would be classed as an aggressive or malignant form of fast-growing cancer.

The most aggressive forms of pineal region tumours tend to spread throughout the central nervous system (CNS), which consists of the brain and spine, but are highly unlikely to spread to other parts of the body.

Treatment options for pineal region tumours

How will we find a cure for pineal region tumours?

Research we are funding across all of our dedicated Research Centres will help lead towards finding a cure for a wide range of brain tumours.

Our team at the University of Plymouth Brain Tumour Research Centre are researching a number of molecular pathways that influence immune system function, tumour metabolism and tumour growth in a range of low-grade brain tumours in children and adults.

The team of research and clinical experts in our Research Centre at Imperial College, London, are studying the way in which the ketogenic diet works in brain cancer, which may have the potential to influence a wide range of brain tumours.

Pioneering research at our Brain Tumour Research Centre at Queen Mary University of London is focused on using GBM stem cells to help develop unique, patient-specific treatments. Their findings are expected to translate into other types of adult and paediatric brain tumours.

We also fund BRAIN UK at Southampton University, the country’s only national tissue bank registry providing crucial access to brain tumour samples for researchers from all clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, and an essential component in the fight to find a cure for pineal region brain tumours.