Acoustic neuromas are benign slow growing tumors of the nerve that connects the ear to the brain (the hearing nerve or eighth cranial nerve). Acoustic neuromas may also be called vestibular schwannomas. When they grow, they press against the hearing and balance nerves. Less than 8% of primary brain tumors are acoustic neuromas. Acoustic neuromas usually develop in middle-age adults.
Learn more about Acoustic neuroma (schwannoma).
Most pituitary tumors are adenomas — tumors that develop from a normal pituitary gland. Adenomas are benign and grow slowly. About 10% of primary brain tumors are adenomas.
Learn more about adenomas and other pituitary tumors.
Cerebrospinal fluid (CSF) is a watery fluid that circulates through the brain’s ventricles (cavities or hollow spaces) and around the surface of the brain and spinal cord. A CSF leak is a condition that occurs when the spinal fluid leaks out of the dura and into another layer of the meninges.
A CSF leak results from a hole or tear in the dura, the outermost layer of the meninges. Causes of the hole or tear can include head injury and brain or sinus surgery. CSF leaks may also occur after lumbar puncture, also called a spinal tap or spinal anesthesia. Spontaneous CSF leaks can occur for no known reason.
Chondromas are very rare benign tumors made of bone cartilage found in the skull. Both the skull base and the paranasal sinuses contain cartilage. Chondromas can develop in this cartilage, typically in people between the ages of 10 and 30.
These tumors grow slowly, but eventually may cause the bone to fracture or grow too much, creating pressure on the brain. In rare instances, chondromas may change into a cancerous condition called chondrosarcomas.
Chondrosarcoma is a malignant bone cancer that mainly affects cartilage. It can begin in cells in the thighbone, arm, pelvis, knee and spine. It may also start in the skull base.
The second most common type of bone cancer, chondrosarcoma occurs most often in people between the ages of 50 and 70. It generally grows slowly, but sometimes develops more rapidly and is likely to spread.
Chordomas are rare, benign and slow-growing tumors. Less than one percent of all primary brain tumors are chordomas. This type of tumor is mostly found at the base of the skull, but sometimes appears in the lower spine. Chordomas can invade adjacent bone and put pressure on nearby nerve tissue.
Choroid plexus tumors are rare tumors that occur most commonly in children under the age of two. About 90% of choroid plexus tumors are benign.
These tumors are found in the choroid plexus — the part of the brain within the spaces in the brain called ventricles that makes cerebrospinal fluid, which surrounds and cushions the brain and the spinal cord. As they grow, choroid plexus tumors can cause hydrocephalus, a build-up of cerebrospinal fluid, commonly known as “water on the brain.” This results in increased pressure on the brain and enlargement of the skull.
Craniopharyngiomas are benign tumors that grow near the pituitary gland. Craniopharyngiomas can be solid tumors or cysts. About 10-15% of pituitary tumors are craniopharyngiomas. They are most common in children, teens and adults older than 50. Craniopharyngiomas often press on nerves, blood vessels or parts of the brain around the pituitary gland.
Learn more about craniopharyngiomas and other pituitary tumors.
Dysembryoplastic neuroepithelial tumors are rare, benign tumors that occur in the tissues covering the brain and spinal cord. These tumors, found in children and teens, can cause seizures.
Encephaloceles are sac-like protrusions of part of the brain and meninges through openings in the skull. These rare birth defects occur when the neural tube, in which the brain and spinal cord form, fails to close completely during fetal development. Skin or, less often, a thin membrane, covers the sac outside the skull.
Encephaloceles can occur in the base of the skull, the top or back of the skull, or between the forehead and nose. Conditions associated with encephaloceles include hydrocephalus (excess accumulation of cerebrospinal fluid in the brain), developmental delays, microcephaly (an abnormally small head), paralysis and seizures.
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 is most common in the skull and facial bones, thighbone, shinbone, ribs, upper arm bone and pelvis.
Fibrous dysplasia can lead to pain and broken or deformed bones. Severe deformity of facial bones can cause loss of vision or hearing. Rarely, an affected bone area can become cancerous.
The exact cause of fibrous dysplasia is not known, but it is believed to be due to a chemical irregularity in a specific bone protein. This bone protein abnormality may be due to a gene mutation present at birth, but it is not known to be an inherited disorder.
Germ cell tumors can be benign or malignant. They grow from germ cells, which form from eggs in women and sperm in men. During normal development of an embryo and fetus, germ cells usually become eggs or sperm. However, if germ cells travel to the brain by mistake, they become tumors.
Germ cell tumors are often diagnosed around the time of puberty. They tend to affect boys more than girls.
Giant cell tumors, named for their extremely large cells, are rare bone tumors that usually affect the leg and arm bones but may be found in the skull. Most giant cell tumors are benign. They usually occur in people between the ages of 20 and 40.
Hemangiopericytomas are rare tumors that involve the blood vessels. They are most common in the legs, pelvic area, head and neck. These tumors may be benign or malignant and can spread to the bone, lungs or liver.
Most hemangiopericytomas are found in soft tissues but some occur in the nasal cavity and paranasal sinuses.
Meningioma is the most common primary brain tumor, accounting for about 33% of all primary brain tumors. Meningiomas originate in the meninges, which are the outer three layers of tissue between the skull and the brain that cover and protect the brain just under the skull. About 85% of meningiomas are benign, slow growing tumors. Some meningiomas grow in the skull base.
Learn more about meningiomas.
Metastatic brain tumors, also called secondary brain tumors, are malignant tumors that originate as cancer elsewhere in the body and then spread (metastasize) to the brain. Metastatic brain tumors are the most common type of brain tumor, occurring about four times more often than primary brain tumors.
Metastatic brain tumors 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).
Learn more about metastatic brain tumors.
Nasopharyngeal angiofibroma, also known as juvenile nasopharyngeal angiofibroma, is a benign tumor in the nose usually found in adolescent boys. It spreads into areas around the nose, causing symptoms such as a stuffy nose and bleeding from the nose.
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 1 (NF1), a genetic disorder formerly known as peripheral NF or von Recklinghausen’s disease.
Olfactory neuroblastomas, also known as esthesioneuroblastomas, are very rare, malignant tumors that develop in the nose. These tumors are believed to start in the olfactory nerve, which transmits impulses related to smell from the nose to the brain.
Osteomas are benign bony outgrowths (new bone growth) mostly found on the skull and facial bones. They are slow growing and generally cause no symptoms. However, large osteomas in some locations may cause problems with breathing, vision or hearing. If the bone tumor grows on another bone, it is called homoplastic osteoma. If it grows on tissue, it is called eteroplastic osteoma.
Cancer of the paranasal sinuses forms in the tissues lining the hollow spaces in the bones around the nose. This malignant cancer is found primarily in the maxillary sinuses, located in the cheekbones under the eyes, and the ethmoid sinuses, beside the upper nose.
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 benign cholesterol granulomas, which are cysts. Other petrous apex lesions include acoustic neuromas and bone cancer.
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 soft-tissue cancer. It can occur in many places in the body but is often found in the head and neck, especially around the eyes. Rhabdomyosarcomas are most common in children. Certain inherited conditions increase the risk of this disease, including neurofibromatosis type 1 (NF1) .
Rathke’s cleft cysts are benign cysts on the pituitary gland. These cysts are benign and grow slowly. They develop in the space between the front and back parts of the pituitary gland. Most Rathke’s cleft cysts are found in adults.
Learn more about Rathke’s cleft cysts and other pituitary tumors.