Brain Tumor Types
- There are more than 120 different kinds of brain tumors, depending onwhere they occur and what kinds of cells they are made of. For instance, meningiomas form in the meninges, and gliomas are composed of glial cells.
- Not all brain tumors are life-threatening. Meningiomas, the most common brain tumor, are often benign and can be treated with surgery.
- Tumor grading is a way of ranking how serious the tumor is – how likely it is to grow and spread.
- Proper diagnosis is essential in determining the best course of treatment for you. Treatment may involve imaging, biopsy and other tests.
Acoustic neuromas (vestibular schwannomas) are benign, slow-growing tumors of the nerve that connects the ear to the brain, which is also known as the hearing nerve or the eighth cranial nerve. When these tumors grow, they press against the hearing and balance nerves, causing hearing loss, ringing in the ear, dizziness and balance problems.
Less than 8 percent of primary brain tumors are acoustic neuromas. Acoustic neuromas usually develop in middle-aged adults.
As the most common type of pituitary tumor, adenomas develop from a normal pituitary gland and tend to grow at a slow rate. About 10 percent of primary brain tumors are diagnosed as adenomas. Fortunately for patients affected by them, adenomas are benign and treatable.
Chondromas are very rare, benign skull base tumors made of bone cartilage found in the skull. They can develop in the cartilage found in the skull base and the paranasal sinuses.
Chondromas typically occur in in patients between the ages of 10 and 30. While these tumors grow slowly, they may eventually cause the bone to fracture or grow too much, creating pressure on the brain. In rare cases, chondromas may change into a cancerous condition called chondrosarcomas.
Chondrosarcoma is a malignant bone cancer that mainly affects cartilage. The second most common type of bone cancer, chondrosarcoma usually develops in patients between the age of 50 and 70.
The tumor can begin in cells in the thighbone, arm, pelvis, knee and spine. It may also start in the skull base. Some of these cancers can be aggressive.
Chordomas are benign, slow-growing tumors usually found in the base of the skull. They may also appear in the lower spine. Less than 1 percent of all primary brain tumors are diagnosed as chordomas. This type of tumor can invade adjacent bone and put pressure on nearby nerve tissue.
Choroid Plexus Tumor
Choroid plexus tumors are rare tumors that are found in the choroid plexus—the part of the brain within the ventricles that produces cerebrospinal fluid. This fluid surrounds and cushions the brain and the spinal cord. About 90 percent of these tumors are benign.
Choroid plexus tumors most frequently occur in children under the age of 2. As the tumors grow, they can cause hydrocephalus, a buildup of cerebrospinal fluid commonly known as “water on the brain.” This can result in increased pressure on the brain and enlargement of the skull.
About 10 percent to 15 percent of pituitary tumors are craniopharyngiomas. These benign tumors grow near the pituitary gland and can appear as solid tumors or cysts. Craniopharyngiomas often press on nerves, blood vessels or parts of the brain around the pituitary gland. They usually affect children and teens as well as adults over age 50.
Dysembryoplastic Neuroepithelial Tumor
Dysembryoplastic neuroepithelial tumors are rare, benign tumors that occur in the tissues covering the brain and spinal cord. Typically found in children and teens, these tumors can cause seizures.
Encephalocele is a sac-like protrusion of the brain and the membranes that cover it through an opening in the skull. This rare birth defect occurs when the neural tube, in which the brain and spinal cord form, fails to close completely during fetal development. Skin or a thin membrane covers the sac outside the skull.
Encephaloceles can occur in the base of the skull, at the top or back of the skull or between the forehead and nose. Conditions associated with encephalocele include hydrocephalus, developmental delays, microcephaly (an abnormally small head), paralysis and seizures.
Each year, about one out of every 10,000 infants born in the United States will have encephalocele, according to the Centers for Disease Control and Prevention.
Fibrous dysplasia is a rare bone disorder in which scar-like fibrous tissue develops instead of normal bone. As the bone grows, the fibrous tissue gradually expands, weakening the bone. Fibrous dysplasia usually develops in the skull base and facial bones, thighbone, shinbone, ribs, upper arm bone or pelvis.
Fibrous dysplasia can lead to pain and broken or deformed bones. Severe deformity of facial bones can cause loss of vision or hearing. In rare cases, an affected bone area may become cancerous.
While the exact cause of fibrous dysplasia is unknown, it may be triggered by a chemical irregularity in a specific bone protein. Although this bone protein abnormality may be due to a gene mutation present at birth, it is not considered an inherited disorder.
Germ Cell Tumor
During normal development of an embryo and fetus, germ cells usually become eggs (in the female) or sperm (in the male). However, if germ cells travel to the brain by mistake, they can become tumors.
Germ cell tumors can be benign or malignant. They are often diagnosed during puberty. They tend to affect boys more than girls.
Giant Cell Tumor
Named for their extremely large cells, giant cell tumors are rare bone tumors that usually affect the leg and arm bones. They may also be found in the skull. Most giant cell tumors are benign and occur in patients between 20 and 40 years of age.
Hemangiopericytomas are rare skull base tumors that involve the blood vessels. They usually develop in the legs, pelvic area, head and neck. While most hemangiopericytomas are found in soft tissues, some may occur in the nasal cavity and paranasal sinuses. These tumors may be benign — if they are malignant they can spread to the bone, lungs or liver.
Meningioma is the most common primary brain tumor, accounting for about 33 percent of all primary brain tumors. Meningiomas originate in the meninges, the outer three layers of tissue that cover and protect the brain just under the skull. About 85 percent of meningiomas are benign, slow-growing tumors. Some meningiomas have been found growing in the skull base.
Metastatic Brain Tumor
Metastatic brain tumors, also called secondary brain tumors, are malignant tumors that originate as cancer elsewhere in the body and then metastasize (spread) to the brain. Metastatic brain tumors are the most common type of brain tumor, occurring about four times more often than primary brain tumors. They can grow rapidly, crowding or destroying nearby brain tissue. Metastatic brain tumors in the skull base most commonly originate from cancer in the breast, colon, kidney, lung or skin (melanoma).
Nasopharyngeal angiofibroma, also known as juvenile nasopharyngeal angiofibroma, is a benign skull base tumor in the nose that is usually diagnosed in adolescent boys. It spreads to areas around the nose, causing symptoms such as congestion and nosebleeds.
Neurofibromas are benign, generally painless tumors that can grow on nerves anywhere in the body. In some cases, these soft, fleshy growths develop in the brain, on cranial nerves or on the spinal cord. Multiple neurofibromas are a symptom of neurofibromatosis type 1 (NF1), a genetic disorder formerly known as peripheral NF or von Recklinghausen’s disease.
Olfactory neuroblastoma, also known as esthesioneuroblastoma, is a very rare, malignant tumor that develops in the nose. This tumor likely starts in the olfactory nerve, which transmits impulses related to smell from the nose to the brain. Patients with olfactory neuroblastomas may experience frequent nosebleeds, lose their sense of smell and have difficulty breathing through their nostrils.
Complex Brain Tumor: Glenn and Jan’s Thank-You to the Johns Hopkins Comprehensive Brain Tumor Center
Osteomas are benign bony outgrowths (new bone growth) that usually develop on the skull base and facial bones. In general, these slow-growing tumors cause no symptoms. However, if large osteomas grow in certain areas of the brain, they may cause problems with breathing, vision or hearing.
If a bone tumor grows on another bone, it is called homoplastic osteoma. If it grows on tissue, it is called heteroplastic osteoma.
Paranasal Sinus Cancer
Cancer of the paranasal sinuses forms in the tissues lining the hollow spaces in the bones around the nose. This malignant skull base tumor is primarily found in the maxillary sinuses (in the cheekbones under the eyes) and the ethmoid sinuses (beside the upper nose).
Petrous Apex Lesion
Petrous apex lesions are abnormalities that occur in the tip of the bone in the skull next to the middle ear. The most common type of petrous apex lesion is a benign cholesterol granuloma, which is a cyst. Other petrous apex lesions include acoustic neuromas and skull base tumors.
Most petrous apex lesions are benign. However, patients with other types of cancer may develop metastatic petrous apex lesions. These are malignant tumors that originate as cancer elsewhere in the body and then spread to the brain.
Rhabdomyosarcoma is a rare form of soft tissue cancer. While it can occur in many places in the body, it is often found in the head and neck and in the skull base — especially around the eyes. Children are the most likely patients to develop rhabdomyosarcomas. Certain inherited conditions, including neurofibromatosis type 1 (NF1), increase the risk of this disease.
Rathke’s Cleft Cyst
Rathke’s cleft cysts are benign pituitary gland tumors that slowly grow in the space between the front and back areas of the pituitary gland. Most Rathke’s cleft cysts are found in adults.