Adult Patient Resource Handbook - 5th Edition
BRAIN TUMOUR TYPES: D - M
DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOUR (DNT)
These tumours are usually located in the temporal lobe and are often associated with seizures that are difficult to control. It is a low-grade tumour and slow growing. This tumour resembles an oligodendroglioma but is different on a cellular level. This distinction is important, as aggressive therapy of DNT is usually not necessary. It is commonly located in the frontal or temporal lobes of the brain. Treatment consists of surgery if necessary and good seizure control.
EPENDYMOMA
These tumours arise from the cells lining the ventricles (hollow channels) of the brain (most commonly the fourth ventricle). As these tumours grow and fill the ventricle, they obstruct the flow of cerebrospinal fluid (CSF) through the brain. These tumours appear more commonly among younger children. There are a number of variants of ependymoma and an anaplastic (fast growing) ependymoma is sometimes found.
Hydrocephalus, caused by the blocking of the flow of cerebrospinal fluid, may make shunting necessary. Total surgical removal is not always possible, and treatment is individualized depending on the type of ependymoma or variant identified. Treatment for fast growing tumours will include radiation (occasionally also given to the spine) and chemotherapy.
EPENDYMOBLASTOMA
These tumours may also arise from ependymal cells and appear to be tumours that begin before the cells have reached a more mature or functional stage of development. Symptoms of these tumours include headache, nausea, vomiting, balance problems and visual disturbances.
GANGLIOGLIOMA
Gangliogliomas are generally slow growing tumours and may occur anywhere in the brain although the temporal lobe and cerebellar hemispheres are the most common sites. They are benign tumours that arise from ganglia-type cells. Treatment is usually total removal by surgery. On occasion, radiation therapy is used.
GERM CELL TUMOUR
Germ cell tumours arise in the pineal region of the brain.
Pineal Region Tumour
The pineal gland is located centrally in the brain and is an out-pouching of the third ventricle. Hydrocephalus is usually a presenting symptom as the cerebrospinal fluid pathway may be blocked. The optic (vision) pathways may also be involved and there may be double vision. Surgery is sometimes possible or a biopsy may be performed to obtain a diagnosis. Some of these tumours are sensitive to radiation. A shunt may be necessary to treat the hydrocephalus, although hydrocephalus may be initially controlled by the use of steroids. Some germ cell tumours may be treated with chemotherapy.
There are four categories of pineal region tumours:
1. Germ cell tumours:
- fast growing:
i. choriocarcinoma
ii. embryonal carcinoma
iii. endodermal sinus tumour
- not as fast growing:
i. germinoma
- slow growing:
i. dermoid cyst
ii. epidermoid cyst
iii. teratoma
iv. yolk sac tumour (Endodermal Sinus Tumour)
2. Pineal cell tumours:
- fast growing:
i. pinealoblastoma
- slow growing:
i. pinealocytoma
These tumours arise from the actual pineal cells of the pineal gland itself. If the cells are dividing quickly, they are considered pinealoblastomas, whereas those tumours with slow growing cells are called pinealomas. Treatment is usually biopsy, or if small, surgical removal. Radiation therapy follows and some centres are using chemotherapy.
3. Glial cell tumours:
Any glial tumour, both slow and fast growing, can be found in the pineal region. These are discussed earlier in this chapter (e.g. astrocytomas).
GLIOBLASTOMA MULTIFORME (GBM) See Astrocytoma.
GLIOMA
These tumours arise from glial cells. There are three types of glial cells: astrocytes, oligodendrocytes and ependymal cells. The following types of gliomas refer to their location within the brain.
Glioma, Brain Stem
Brain stem gliomas are astrocytomas that usually start in the pons.
Ten to twenty-five percent (10%-25%) of pediatric brain tumours will be brain stem gliomas. These gliomas only make up 2-3% of all intracranial tumours in adults, and are more likely to be low grade and remain localized.
These tumours occur equally between sexes and most often occur between the ages of 5-10 years. Brain stem gliomas are located in an area of the brain and spinal cord that is responsible for many vital body functions. These include vision, balance, strength, gagging, coughing and swallowing.
Because of the location of these tumours, surgery is rarely an option (except for biopsy and draining of cyst). Radiation to the mass is the usual method of treatment. Some centres may add chemotherapy before or after radiation treatment. These are generally considered tumours of childhood.
Glioma, Butterfly
When a glioma spreads across the corpus callosum into both hemispheres, it often has the appearance of a butterfly on a CT or MRI scan and is given the general term "butterfly glioma".
Glioma, Optic Nerve
Optic nerve gliomas are located along the optic nerves, the optic chiasm and the hypothalamus. (See Visual Changes, Chapter 7) These tumours are usually slow growing (astrocytomas). Symptoms will vary depending on location but may include decreased vision, double vision and papilledema (swelling of the optic nerve). If vision has been lost, surgery may be considered. If visual function remains, there will be careful follow-up with imaging studies done at regular intervals. Radiation therapy may be an option. For tumours that involve the hypothalamus and the third ventricle, there may be signs of hydrocephalus as well as hormone imbalance.
Surgical treatment of hydrocephalus may be considered. Some tumours located here respond well to chemotherapy and it may be considered. These tumours are usually associated with Neurofibromatosis Type 1 (a type of genetic disorder that affects the skin and nervous system).
Glioma, Mixed
You may hear this term used. A tumour may be composed of two or more cell types (as seen under the microscope). These tumours are classified into oligo-astrocytoma in which the two predominant cells identified are the oligodendroglial cells and astrocytoma cells. In this tumour, both of these cell groups appear to be "tumour-like". At times, malignant features are identified. In this situation, the tumour is identified as an anaplastic (malignant) oligo-astrocytoma.
These tumours are treated based on the more prominent cell group identified. Treatment may depend on the size, location, and the diagnosis. The presence of specific genetic changes may be very useful in categorizing these tumours. The prognosis of these tumours may be more determined by the characteristics and numbers of astrocytic cells present.
Glioma, Multicentric
You may hear this term applied to glial tumours that, on investigational studies, appear to be located in two widely separated parts of the brain (eg. left frontal and right temporal). The multiple locations of these tumours usually make complete surgical resection very difficult.
These tumours may be treated with radiation therapy and chemotherapy depending on the exact tumour type.
Oligodendroglioma
These tumours are slow growing and can be low grade (grade II) or high-grade (grade III). The mass usually appears calcified (calcium deposits) on imaging (CT scan or MRI scan) showing that it has been there for many years. Some of these tumours are malignant when first diagnosed and are referred to as anaplastic (malignant) oligodendrogliomas. These tumours arise from the oligodendroglial cells, which make up the myelin that insulates nerve fibres. More than 60% of oligodendrogliomas are found in the frontal lobe.
Symptoms of these tumours may include seizures, headache and vision problems. Treatment usually involves surgical removal along with a course of chemotherapy and/or radiation therapy if sub-totally (incompletely) removed. These tumours are often chemo-sensitive and recent advances in genetic testing are helping to determine the appropriate treatment path for these tumours. Specific changes in chromosomes 1 and 19 are found in about 50% of these tumours and influence the treatment period.
HEMANGIOBLASTOMA
These tumours may develop from and are composed of blood vessels. These tumours occur most frequently in the cerebellum but can be elsewhere in the brain or spinal cord. These tumours grow slowly and symptoms depend on location. Treatment includes surgery and possibly radiation. These tumours may run in families.
Von Hippel-Lindau Disease
This is a genetically dominant disorder. Hemangioblastomas, often in the cerebellum, are the most common brain tumours associated with this disease. Hemangioblastomas are associated with the retina of the eye and, if not treated, can lead to blindness. Treatment is usually surgery for the brain tumour.
Laser coagulation can be used for retinal lesions. Malignant kidney tumours are common in this disorder. Other types of abnormal tumours are also common.
To learn more about this disorder, contact the Canadian VHL Family Alliance at 1-800-767-4845 or http://vhlcanada.ca
LIPOMA
This is a mass, which is made up of normal adipose (fatty) tissue and is usually situated just below the skin. Lipomas may be watched over time to see if they grow. Surgical removal may be indicated but location of the mass has to be considered. Lipomas are common in the spinal cord associated with congenital malformations. Rarely, lipomas can be found in the corpus callosum.
LYMPHOMA
Lymphomas arise from specialized cells of the lymphatic system and occur both in the brain and spinal cord. The incidence is increased in patients after organ transplantation and patients whose immune system is depressed (e.g. AIDS). These tumours are frequently responsive to steroid medication. Surgery and radiation may be indicated along with chemotherapy. Lymphomas starting elsewhere in the body may spread to the brain or spinal fluid and it is not unusual for this tumour to be found in multiple places.
To learn more about Lymphoma, contact Lymphoma Foundation Canada at 1-866-204-0233 or www.lymphoma.ca
MEDULLOBLASTOMA
Medulloblastomas make up twenty percent (20%) of all pediatric tumours, however this tumour occurs infrequently in adults, and represents 1% of primary adult brain tumours.
These tumours are fast growing and symptoms include a short, progressive history of headaches, vomiting, loss of appetite and coordination difficulties. Spread outside of the brain and spinal cord is rare although it may occur. Very often, these tumours have spread within the central nervous system before diagnosis. Spread through the CSF is possible (See Carcinomatous Meningitis under Metastatic / Secondary Brain Tumour in this chapter).
Treatment almost always involves surgery with the goal of removing all (gross total) or as much as possible (subtotal) of the tumour. Radiation is very effective against this tumour and is generally done to the entire head and spinal cord because of the high possibility of seeding malignant cells by way of the cerebrospinal fluid. An effective chemotherapy protocol has been developed and the outlook for this type of tumour has improved dramatically over the past ten years. Shunting may be necessary to treat hydrocephalus caused by the tumour interrupting the pathways of the cerebrospinal fluid.
Depending on the age of the patient, the amount of resection and the spread of the disease, a high and a low risk group of medulloblastoma patients have been identified. Treatment is now based on these parameters.
MENINGIOMA
These tumours arise from the arachnoid cells in the meninges (the outer protective layer of tissue surrounding the brain) and are almost always slow growing and benign. They are usually firm, enclosed tumours, which can become large before symptoms appear. These tumours cause pressure on the brain and can invade neighbouring bone. Unless they are malignant (very rare) they do not invade the brain. The symptoms produced by meningiomas depend on size, location and growth rate of the tumour.
Symptoms are usually related to malfunction in the part of the brain that is being depressed. These tumours tend to have many blood vessels but can often be completely removed. Incomplete removal may be related to the closeness of important blood vessels. In certain situations, blood vessels feeding the tumour may be embolized (blocked). This may improve the ability of the neurosurgeon to remove the tumour.
METASTATIC / SECONDARY BRAIN TUMOUR
The brain is frequently the site of metastasis (spread) from a tumour elsewhere in the body. In major referral centers, metastatic disease is the most frequent type of brain or spinal cord tumour seen. The most common sites of cancer that spreads to the brain are lung, breast, kidney and skin (melanoma). The spread of a tumour to the brain may produce symptoms before the primary tumour is diagnosed.
Most tumours that spread to the brain do so via the blood stream and lodge between the gray and white matter. This often causes edema or swelling and hence the most frequent symptom of brain involvement is headache related to the increased pressure.
Tumours that spread to the brain may be single (solitary metastasis) or multiple. A single metastasis may be removed with surgery. Radiation therapy is also used for single or multiple metastases. If a solitary metastasis recurs, or a new solitary metastasis develops, re-operation may be a consideration as well as an alternate form of radiation therapy. Standard radiation cannot be given twice. An alternative form of radiation therapy would be stereotactic radiosurgery.
Carcinomatous Meningitis (Also known as "spinal fluid metastasis")
Tumour cells can grow in the fluid around the brain (cerebrospinal fluid). This can give the picture of meningitis at first. Treatment involves radiation or direct placement of drugs in the cerebrospinal fluid. This may be accomplished through an Ommaya Reservoir. Although this condition is more common in metastatic tumours, it may occur in other tumours as well.
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