Introduction of pineal tumours

Pineal tumours can be described as a type of brain tumour and a primary central nervous system tumour, meaning abnormal growths can develop in the pineal gland in the brain and spread to the spinal cord. ^1,2 These tumours are rare, with less than 1% occurring in the pineal gland.¹

Overview of the pineal gland^6,7

Location and function of the pineal gland³

• The pineal gland is a small structure in the centre of your brain that functions as the body’s internal timekeeper, regulating your daily rhythm - circadian rhythm
• In order to help you wake up or sleep, the pineal gland functions by sensing whether it's light or dark in the environment. Once it has sensed whether it is light or dark in the environment, it signals the body through the production of a hormone called melatonin
• The decrease in melatonin during the day signals your body to wake up, and the increase in melatonin during the evening signals your body to sleep!⁴

This highlights the importance of the pineal gland, and any abnormalities in the pineal gland can potentially affect the regulation of sleep, resulting in the disruption of overall well-being.⁵   

Pineal tumours in the brain^1,13,16

• Tumours that begin in the pineal gland are deeply located in the brain
• Can result in compression of structures in the brain, e.g., cerebral aqueduct, brain stem, and cerebellum
• These structures can be compressed, interrupting vital processes within the brain. For instance, safeguarding the brain, removing waste and providing nutrients
• When processes are interrupted, this can lead to the buildup of fluid (i.e. cerebrospinal fluid) in the brain. As a result, it increases the pressure within the brain
• The presence of a pineal tumour in the brain can lead to the emergence of conditions that distinctly exhibit signs and symptoms. Refer to the signs and symptoms for more information

Types of pineal tumours^1,6,8   

There are three types of pineal region tumours: 

1. Germ cell tumours
2. Pineal gland tumours/pineal parenchymal tumours 
3. Pineal metastasis

Germ cell tumours^1,6,8

• Germ cells can give rise to eggs in females and sperm in males
• ‘Germ cell tumours’ develop from reproductive cells, typically occurring in the reproductive organs, such as the ovaries and testes
  • It can also develop in other areas, including the chest, brain and pineal gland
• The most common type of pineal tumour, accounting for 60% of pineal tumours 
• Can be further subdivided into two groups: germinoma and non-germinomatous tumours
• Non-germinomatous tumours can be further subdivided, including embryonal carcinoma, yolk sac tumour, choriocarcinoma, mature/immature teratoma, and mixed germ cell tumours

Pineal gland tumours/pineal parenchymal tumours^1,6,8

• Tumours begin in the pineal gland 
• Occurs half as frequently compared to germ cell tumours 
• Can be further subdivided: pineocytoma, pineal parenchymal tumours of intermediate differentiation, papillary tumour, pineoblastoma and desmoplastic myxoid tumour of the pineal region (SMARCB1-mutant) 

Common pineal gland tumour types: grades and descriptions

Pineal metastasis⁶

• Very uncommon
• Lung carcinoma, pancreatic, oesophageal, and bladder neoplasm can potentially metastasise or spread to the pineal gland.   

Symptoms of pineal tumours^13,14,15

The signs and symptoms of a pineal tumour progress slowly from weeks to years. However, if a tumour grows rapidly, this could lead to the onset of acute and severe symptoms. As mentioned previously, the tumour growth in the brain can impact surrounding structures and functions. It is also important to note that the symptoms patients may exhibit may vary and can also depend on the type of pineal tumour they have. 

The following signs and symptoms can include the following: 

• The most common symptom patients have, approximately 90%, is obstructive hydrocephalus.
• The fluid (i.e. cerebrospinal fluid) buildup in the brain subsequently increases the pressure (intracranial pressure) in the brain, leading to intracranial hypertension. 
• Hence, patients may experience the following symptoms as a result: 
  • New/severe headache 
  • Nausea 
  • Vomiting 
  • Memory loss
  • Difficulty walking and loss of coordination
  • Difficulty controlling urine
  • Sensitivity to light 
  • Mental changes and mental decline 
  • Consciousness - ranging from confusion to severe drowsiness or even loss of consciousness 
  • Tired/lethargic
• While not as common, patients may present eye-related symptoms and conditions.
  • Parinaud syndrome
  • Diplopia is a vision condition whereby an individual can see two images when looking at a single object
  • Dilated pupils 
  • Difficulty with eye coordination and movement
• Symptoms related to the endocrine system 
  • Hypothalamus/pituitary gland dysfunction
  • Diabetes insipidus - excessive thirst or urination 
  • Disorders related to puberty - precocious puberty
  • Fatigue 
  • Gynaecomastia 
  • Anorexia
  • Low libido 
• Other infrequent symptoms such as motor/sensory (e.g., paresthesia and ataxia), and psychiatric (e.g., anxiety and depression)

Diagnosis^1,13,17

If your doctor suspects you might have a pineal tumour, they may recommend the following diagnostic tests: 

• Pineal region tumours can be diagnosed using imaging techniques such as MRI and CT  scan to identify features of the tumour, such as the size and location
• Biopsy - small samples of the tumour are surgically removed and sent to the lab for examination
• Lumbar puncture for cerebrospinal fluid analysis - obtaining a sample of cerebrospinal fluid via a needle inserted in the lower back. This is to identify whether the signs and symptoms the patient is experiencing are a result of a brain/spine disorder
• Blood test - identify tumour markers in the blood that can help provide additional information and guide the diagnosis of a pineal tumour in patients

Treatment options^1,13

Your specialist may plan and offer the following treatments depending on the type of pineal region tumour, size, grade and symptoms you display. 

Surgery

• May be conducted for definitive histological diagnosis of tumour type, meaning tissue is examined via a microscope for more detailed reports regarding the tumour. 
• Specialists remove the pineal tumour or as much of it as possible from the brain
• This may be the only type of treatment you may need.

Radiotherapy

•  Controls tumour growth 
• This may be the only type of treatment you may need.

Chemotherapy

• Kills brain tumour cells 
• Chemotherapy may be recommended for patients in conjunction with radiotherapy.

Combined treatment

• Surgery, chemotherapy, and radiotherapy may be recommended for high-grade tumours
• Radiotherapy might be advised post-surgery 
• Both radiotherapy and chemotherapy could be recommended in cancer recurrence

Clinical trial

• Your specialist or medical team may offer you the opportunity to take part in a clinical trial to test a new type of treatment.

Your specialist will provide more details regarding side effects and complications associated with your treatment. 

Prognosis and outlook

Survival rates^2,13

• The 5-year survival rate for pineal region tumours: 65 to 69.5%  
• However, your prognosis can also depend on:
  • Pineal region tumour characteristics 
  • Type of pineal region tumour 
  • Tumour grade 
  • Patient’s age  
  • Patient’s health 
  • Response to treatment

Refer to your specialist for more information and details regarding your prognosis. 

Follow-up care and monitoring^1,13

• Appointments may be scheduled regularly after completion of treatment
• Patients may be monitored every 1-2 years by a specialist
• Advised to conduct MRI scan and biomarker analysis periodically, regardless of whether outcomes appear normal.
• Children diagnosed with pineal region tumours are recommended for lifelong follow-up
• The follow-up your specialist may request varies based on the individual

Summary 

• A pineal tumour is a brain tumour that can begin in the pineal gland
• Pineal tumours can be classified into one of three main types: germ cell tumour, pineal gland tumour or pineal metastasis
• Pineal tumours can be further classified into subgroups
• The most common indication of pineal tumour in patients is the occurrence of obstructive hydrocephalus, typically accompanied by symptoms such as headaches, nausea and vomiting
• Diagnosis enables and guides the type of treatment the patient may require
• Patients may be recommended the following treatment by itself or in combination: surgery, chemotherapy and radiotherapy