Ependymoma
   HOME

TheInfoList



OR:

An ependymoma is a
tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
that arises from the
ependyma The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous s ...
, a tissue of the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
. Usually, in pediatric cases the location is
intracranial The cranial cavity, also known as intracranial space, is the space within the skull that accommodates the brain. The skull is also known as the cranium. The cranial cavity is formed by eight cranial bones known as the neurocranium that in human ...
, while in adults it is spinal. The common location of intracranial ependymomas is the floor of the
fourth ventricle The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ...
. Rarely, ependymomas can occur in the
pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproduc ...
.
Syringomyelia Syringomyelia is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. Often, syringomyelia is used as a generic term before an etiology is determined. This cyst, called a syrinx, can expand and elongate ...
can be caused by an ependymoma. Ependymomas are also seen with neurofibromatosis type II.


Signs and symptoms

Source: Symptoms are dependent on the location and severity of the tumor. Intracranial ependymomas: * severe headache * nausea * vomiting * visual loss (due to
papilledema Papilledema or papilloedema is optic disc swelling that is caused by increased intracranial pressure due to any cause. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare. In ...
) * loss of balance * vertigo *
hydrocephalus Hydrocephalus is a condition in which cerebrospinal fluid (CSF) builds up within the brain, which can cause pressure to increase in the skull. Symptoms may vary according to age. Headaches and double vision are common. Elderly adults with n ...
* drowsiness (after several hours of the above symptoms) Spinal ependymomas: * bilateral Babinski sign * gait change (rotation of feet when walking) * impaction/constipation * back flexibility


Morphology

Ependymomas are composed of cells with regular, round to oval nuclei. There is a variably dense fibrillary background. Tumor cells may form gland-like round or elongated structures that resemble the embryologic
ependymal canal The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it r ...
, with long, delicate processes extending into the lumen; more frequently present are perivascular
pseudorosette In histopathology, a palisade is a single layer of relatively long cells, arranged loosely perpendicular to a surface and parallel to each other. A rosette is a palisade in a halo or spoke-and-wheel arrangement, surrounding a central core or hub. ...
s in which tumor cells are arranged around vessels with an intervening zone consisting of thin ependymal processes directed toward the wall of the vessel. It has been suggested that ependymomas are derived from radial glia, despite their name suggesting an ependymal origin. Image:Myxopapillary ependymoma - high mag.jpg,
Micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...
of a myxopapillary ependymoma. HPS stain. File:Ependymom ax T2.jpg, Ependymoma of 4.ventricle in MRI. File:Ependymom sag FLAIR.jpg, Ependymoma of 4.ventricle in MRI. File:Ependymom cor T1KM.jpg, Ependymoma of 4.ventricle in MRI. Left without, right with contrast-enhancement.


Ependymoma tumors

Ependymomas make up about 5% of adult intracranial
glioma A glioma is a type of primary tumor that starts in the glial cells of the brain or spinal cord. They are malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain and central nervous system tumors and 80% of ...
s and up to 10% of childhood tumors of the central nervous system (CNS). Their occurrence seems to peak at age 5 years and then again at age 35. They develop from cells that line both the hollow cavities of the brain and the
central canal The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it r ...
containing the spinal cord, but they usually arise from the floor of the
fourth ventricle The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ...
, situated in the lower back portion of the brain, where they may produce headache, nausea and vomiting by obstructing the flow of cerebrospinal fluid. This obstruction may also cause
hydrocephalus Hydrocephalus is a condition in which cerebrospinal fluid (CSF) builds up within the brain, which can cause pressure to increase in the skull. Symptoms may vary according to age. Headaches and double vision are common. Elderly adults with n ...
. They may also arise in the spinal cord, conus medullaris and supratentorial locations. Other symptoms can include (but are not limited to): loss of appetite, difficulty sleeping, temporary inability to distinguish colors, uncontrollable twitching, seeing vertical or horizontal lines when in bright light, and temporary memory loss. It should be remembered that these symptoms also are prevalent in many other illnesses not associated with ependymoma. About 10% of ependymomas are
benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...
myxopapillary ependymoma (MPE). MPE is a localized and slow-growing low-grade tumor, which originates almost exclusively from the lumbosacral nervous tissue of young patients. On the other hand, it is the most common tumor of the lumbosacral canal comprising about 90% of all tumoral lesions in this region. Although some ependymomas are of a more
anaplastic Anaplasia () is a condition of cells with poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells. The term also refers to a group of mor ...
and
malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...
type, most of them are not anaplastic. Well-differentiated ependymomas are usually treated with surgery. For other ependymomas, total surgical removal is the preferred treatment in addition to radiation therapy. The malignant (anaplastic) varieties of this tumor, malignant ependymoma and the ependymoblastoma, are treated similarly to medulloblastoma but the prognosis is much less favorable. Malignant ependymomas may be treated with a combination of radiation therapy and chemotherapy. Ependymoblastomas, which occur in infants and children younger than 5 years of age, may spread through the cerebrospinal fluid and usually require radiation therapy. The subependymoma, a variant of the ependymoma, is apt to arise in the fourth ventricle but may occur in the
septum pellucidum The septum pellucidum (Latin for "translucent wall") is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the f ...
and the cervical spinal cord. It usually affects people over 40 years of age and more often affects men than women. Extraspinal ependymoma (EEP), also known as extradural ependymoma, may be an unusual form of
teratoma A teratoma is a neoplasia, tumor made up of several types of biological tissue, tissue, such as hair, muscle, Human tooth, teeth, or bone. Teratomata typically form in the tailbone (where it is known as a sacrococcygeal teratoma), ovary, or test ...
or may be confused with a
sacrococcygeal teratoma Sacrococcygeal teratoma (SCT) is a type of tumor known as a teratoma that develops at the base of the coccyx (tailbone) and is thought to be primarily derived from remnants of the primitive streak. Sacrococcygeal teratomas are Benign tumor, benign ...
.


Classifications

Ependymomas are classified by their location, cellular features, and more recently, molecular characteristics. The three locations are defined as supratentorial, posterior fossa (also referred to as infratentorial), and spinal. They are classified as Grade I, Grade II, or Grade III. Within the last decade, ependymomas have been further characterized by 10 molecular subtypes. Ependymoma tumor location, grade, and molecular features determine the treatment plan and prognosis. Intracranial ependymomas, including supratentorial and posterior fossa, make up 90% of ependymomas in children. The supratentorial region is the upper brain region, or cerebrum, and contains the lateral and third ventricles. The posterior fossa, or infratentorial, is behind or below this region in the area of the brainstem and cerebellum and contains the fourth ventricle. A majority of intracranial pediatric ependymomas are in the posterior fossa. Patients with intracranial ependymomas typically present with increased intracranial pressure that results in headaches, dizziness, nausea, and vomiting. The third location of ependymomas is within the central canal of the spinal cord. Spinal ependymomas comprise about 65% of adult ependymomas and most often occur in the lumbosacral region. Patients with spinal ependymomas can present with back pain, numbness or weakness in the limbs, and urinary or bowel problems. The World Health Organization classifies ependymomas as Grade I-III. Grade I tumors are low-grade and include the subependymoma subtype, which is more common in adults. Grade II tumors include myxopapillary and conventional ependymoma, which are identified by the presence of perivascular pseudorosettes. Grade III anaplastic ependymomas are the most severe and fast-growing tumors.


Molecular Subtypes

There have been 10 identified molecular features of ependymomas. There are three molecular subtypes in the supratentorial location, three molecular subtypes in the posterior fossa location, and four molecular subtypes in the spinal cord. Each location has 1 molecular subtype classified as Grade I subependymoma and is found primarily among adults with good prognoses. The molecular subtypes: ZFTA and YAP1 are found in the supratentorial region of the brain, are classified as Grade II/III and have been identified in infants, children, and adults. Posterior Fossa Group A and Group B are the two molecular subtypes classified as Grade II/III in the posterior fossa region of the brain. Posterior Fossa Group A has become a therapeutic target within preclinical research due to its poor prognosis among infants and children, but clinical research is many years away. Spinal ependymomas have three molecular subtypes classified as Grade II/III: MPE, EPN, and MYC, ranging from good to poor outcomes, respectively. Since these are found primarily within the spinal cord, they have been identified mainly in adult patients. Key: subependymoma (SE), myxopapillary ependymoma (MPE), ependymoma (EPN)


Treatment

Guidelines for initial management for ependymoma are maximum surgical resection followed by radiation. Chemotherapy is of limited use and reserved for special cases, including young children and those with tumor present after resection. Prophylactic craniospinal irradiation is of variable use and is a source of controversy given that most recurrence occurs at the site of resection and therefore is of debatable efficacy. Confirmation of cerebrospinal infiltration warrants more expansive radiation fields. Prognosis of recurrence is poor and often indicates palliative care to manage symptoms.


References


External links


Brain and Spinal Tumors: Hope Through Research (National Institute of Neurological Disorders and Stroke)
{{Authority control Brain tumor Rare cancers Infectious causes of cancer Ventricular system