Overview

Pineoblastoma is a rare type of brain cancer where a malignant tumour growth occurs in the pineal gland, located in the centre of the brain. It is more common in children and represents about 1% of intracranial tumour cases.¹ Pineoblastomas are the most aggressive form of tumours that can occur in the pineal region, and have the ability to spread to the spinal cord, making it very difficult to treat.

What is pineoblastoma?

Pineoblastoma is a rare type of cancer that grows in the brain’s pineal gland, a tiny pinecone-shaped gland located in the brain's centre. The pineal gland is associated with controlling our circadian rhythm (our sleep-wake cycle) and is associated with the production of melatonin, which is important in regulating sleep.² It is also associated with puberty and reproductive functions. For example, melatonin influences the time, duration, and frequency of menstrual periods. 

Because pineoblastomas are aggressive in nature, the World Health Organisation (WHO) normally classifies them as Grade 4 (highest grade, most severe form).³ This form of cancer is more common in younger children and is rarely seen in adults. Children under the age of 4 have a low five-year survival rate of 8.3% while children over 4 years old have a survival rate between 60-69%.⁴ It is equally common in people assigned male or female at birth.

Possible causes

Due to its rarity, pineoblastoma remains heavily understudied in scientific research. The majority of studies are based on individual case study scenarios or larger studies also involving other forms of cancer. However, recent findings have shown that the adult form of the tumour is comparatively less aggressive since the paediatric form is driven by a particular set of molecular changes, making the nature of the tumour much more aggressive.⁵

Pineoblastoma can run in the family if linked to certain inherited mutations. These mutations can lead to errors in proteins that control small molecules called microRNAs – these molecules monitor gene activity, turning on and off certain genes.⁵ If this process remains uncontrolled, it can drive the formation of tumours. However, these changes in gene activity and cell functioning can also occur sporadically without any genetic history of mutations.

Symptoms of pineoblastoma

Symptoms of pineoblastoma can vary depending on the size and location of the tumour, as well as the age of the patient. Common symptoms include:

• Hydrocephalus: build-up of pressure within the skull as a result of cerebrospinal fluid entering the area
• Headaches
• Feelings of nausea
• Double vision
• Eye movement problems, such as difficulty looking up
• Balance and coordination issues
• Changes in behaviour such as irritability, lethargy or other personality changes
• Disturbances in sleep since the pineal gland regulates the sleep-wake cycle

Diagnosis of pineoblastoma

Diagnosing pineoblastoma involves a combination of imaging studies, clinical evaluations, and histopathological analysis. Key steps in the diagnostic process include:

• Imaging tests: Both computerised tomography (CT scan) and magnetic resonance imaging (MRI scan) can be used for tumour characterisation – to find the location, size and shape of the pineal tumour.
• Biopsy: Biopsy involves removing a sample of tissue for testing (it is either done before surgery with a needle where a small piece of tissue is removed or removed during surgery). The tissue sample is then analysed in a lab, and this is used to confirm the presence of pineoblastoma once the scans have been completed.
• Lumbar puncture: Lumbar puncture is a process in which a sample of spinal fluid is removed from around the brain and spinal cord (also called a spinal tap) where a needle is inserted between two bones in the lower spine and the cerebrospinal fluid is removed to look for pineoblastoma cells.

Management and treatment of pineoblastoma

While there isn’t a cure available for pineoblastoma just yet, there are some treatment options which focus on reducing the tumour size and helping to manage symptoms.

Surgery

Surgeons usually aim to reduce the tumour size or attempt to remove it completely (maximal resection). However, due to the position of pineoblastomas which are usually deep within the brain, it is not always a viable option as it can risk more damage, especially if the tumour has spread to other areas within the brain.

Surgery may also be recommended to drain the build-up of fluid, and there is a minimally invasive option available known as endoscopic third ventriculostomy.

Radiotherapy and chemotherapy

Radiotherapy and chemotherapy interventions are employed to target and control the growth of pineoblastoma cells. This form of treatment is usually combined, and often used post-surgery, to maximise the effectiveness of targeting the rapidly growing and invading tumour cells. 

Radiotherapy uses high-energy light sources such as X-rays or electron beams to destroy cancer cells and slow down their growth. This is the most used form of treatment for pineoblastomas and can be used on the entire brain and spinal cord. Post-surgery therapy has been related to a higher overall survival rate. ⁶ Furthermore, radiotherapy can affect endocrine function including growth, energy levels and fertility.

Chemotherapy uses very strong cancer-killing medication (often combined with radiotherapy or surgery) to destroy circulating tumour cells and can target the entire body rather than a specific area. However, chemotherapy also affects normal healthy cells which can lead to side effects such as nausea, loss of appetite, hair loss, infection and fatigue. Steroids may also be prescribed to help manage the swelling.

Pineoblastoma can be very difficult to treat as symptoms can worsen over time and there is a possibility of the cancer returning after treatment. It is very difficult to fully remove the tumour without possibly damaging other parts of the brain but utilising all options can make treatment strategies as effective as possible.

Risk factors of pineoblastoma

There is no known way to prevent pineoblastoma. Patients may be at higher risk of developing pineoblastoma if they have retinoblastoma (another type of cancer that affects the retina). The combination of retinoblastoma and pineoblastoma is called trilateral retinoblastoma.^7,8

Summary

Pineoblastoma is a rare type of cancer that grows in the brain’s pineal gland. This form of cancer is more common in children and is rarely seen in adults. Symptoms of pineoblastoma include hydrocephalus, headaches, nausea and vision problems. Diagnosis of pineoblastoma is done using MRI and CT scans, biopsy and/or by checking the cerebrospinal fluid from a lumbar puncture. Management of the disease can be done by surgery, radiotherapy, chemotherapy or all three combined, which is usually tailored to the specific characteristics of the tumour and the patient's overall health. Early detection and diagnosis are crucial for effective treatment and improving prognosis. Despite the challenges associated with treating pineoblastoma, ongoing research and clinical trials continue to seek more effective therapies to improve outcomes for affected children​.