Pineal region tumours are cancers of the pineal gland in the brain, or the tissues surrounding it. The pineal gland is a small, pea-shaped organ in the centre of the brain that is responsible for the production and secretion of melatonin (which is more commonly known as the sleep hormone) in dark settings. Its primary functions are to regulate your 24-hour internal body clock (or circadian rhythm), as well as assisting with the initiation and maintenance of sleep.
The development of a pineal region tumour can result in blockages of cerebrospinal fluid (CSF), which provides protection, nourishment and waste removal in the central nervous system (CNS). The CNS is responsible for all sensory and motor functions in the body, and is composed of the brain and the spinal cord.
Pineal region tumours are more common in males, and tend to occur more in children and young adults. However, anyone can develop this disease.
Types of Pineal Region Tumours
There are three main types of pineal region tumours, which are classified by the types of cells the cancer originates from.
Germ Cell Tumours
Germ cell tumours (GCTs) are cancers that develop from germ cells, the biological cells that develop into the gametes (or reproductive cells), such as the ovum and sperm. In most cases, GCTs in the pineal gland region are germinomas. However, they can also develop as nongerminomatous GCTs, which include:
- Embryonal carcinomas.
- Endodermal sinus tumours (also known as yolk sac tumours).
- Mixed tumours (tumours with features of different GCTs).
For more information on GCTs in the brain, please refer to the Rare Cancers Australia Germ Cell Tumours (Intracranial) page.
Gliomas are a type of brain tumour that start in the glial cells of the CNS. Glial cells (or glia) provide structural and physiological support to neurons in the CNS. There are three types of glial cells:
- Astrocytes – tumours that start from astrocytes are called astrocytomas or glioblastomas.
- Oligodendrocytes – tumours that start from oligodendrocytes are called oligodendrogliomas.
- Ependymal cells – tumours that start from ependymal cells are called ependymomas.
Gliomas may occur in or around the pineal gland.
Pineal Gland Tumours
Pineal gland tumours originate from pinealocytes (also known as parenchymal cells), which are the main cells of the pineal gland. These cells responsible for the production and secretion of melatonin in the body. There are four primary types of pineal gland tumours.
Pineocytomas are very rare tumours that are often classified as grade I (unlikely to metastasise). Unlike most pineal region tumours, pineocytomas are most commonly diagnosed in women and adults between the ages of 30-60 years old. These tumours are usually slow-growing and non-aggressive. The prognosis for pineocytomas is often excellent.
Pineal Parenchymal Tumours of Intermediate Differentiation
Pineal parenchymal tumours of intermediate differentiation are very rare tumours that are often classified as grade II or grade III. This type of tumour has features of both pineocytomas and pineoblastomas. They are more common in women, and people between the ages of 20-70. While these tumours can be aggressive, they can have a good prognosis when caught early.
Papillary Tumours of the Pineal Region
Papillary tumours of the pineal region are very rare tumours that are often classified as grade II or grade III. In some cases, papillary tumours in the pineal region are indistinguishable from pineocytomas or normal pinealocytes. The ages that this tumour is often found ranges from 15 months to 67 years, and there have been few cases of this disease reported. In some cases, this cancer is likely to recur and can be aggressive.
Pineoblastomas are rare and aggressive tumours that are usually classified as grade IV (likely to metastasise). They are the most common type of pineal gland tumour, and mostly affect children under the age of two. Pineoblastomas are extremely aggressive, and may not carry as good of a prognosis as other pineal region tumours.
If a pineal region tumour is detected, it will be graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Unlike most cancers, cancers in the brain are not staged, only graded. Grading helps your doctors determine the best treatment for you.
Brain cancers are often given a grade from I to IV:
- Grade I (low grade): cells look mostly normal. They are slow growing and rarely recur after treatment.
- Grade II (low grade): cells look slightly abnormal. They are usually slow growing and may recur after treatment.
- Grade III (high grade): cells look more abnormal. They may be fast growing and may have already metastasised.
- Grade IV (high grade): cells look very abnormal. They are usually fast growing and have already metastasised. May have high recurrence rate.
Once your tumour has been graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on a variety of factors, including grade, type, patient age and location of the tumour. Treatment options for pineal region tumours may include:
- Radiation therapy.
- Surgery, potentially including:
- Shunt insertion (to drain fluid build-up in the brain).
- Resection (to remove as much as the tumour as possible – may not be able to resect it all due to its location within the brain).
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia Treatment Options page.
Because of how rare pineal region tumours are, there has been limited research done into the risk factors of this disease.
The symptoms of a pineal region tumour may include:
- Hydrocephalus (fluid build-up in the brain), which carries its own set of symptoms:
- Nausea and/or vomiting.
- Difficulties with eye movement.
- Difficulties with balance.
- Difficulties with walking.
- Memory problems.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
If your doctor suspects you have an pineal region tumour, they will order a variety of tests to confirm the diagnosis and refer you to a specialist for treatment.
A neurological examination assesses sensory and motor functions, and can generally be done in your GPs office. The doctor may check your vision, hearing, balance, coordination, strength and reflexes, depending on the signs and symptoms you have described. Any problem that is detected in this exam can help determine which portion of the CNS needs further investigation.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-ray, and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
A lumbar puncture, or spinal tap, involves inserting a needle between two vertebrae in the lower spine and extracting a sample of cerebral spinal fluid (CSF) for analysis. A local anaesthetic or sedative is given prior to the procedure. Your doctor will discuss any risks and possible complications with you prior to the procedure.
Once the location(s) of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. This can be done by either a punch biopsy, a fine needle aspiration, and/or a lymph node biopsy. The samples are then analysed for cancer cells.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on stage, rate/depth of tumour growth, susceptibility to treatment, age, overall fitness and medical history. Generally, early-stage pineal region tumours have a good prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence.
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.