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A subependymoma is a type of
Patients are often asymptomatic, and are incidentally diagnosed. Larger tumours are often with increased intracranial pressure.
brain tumor
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secon ...
; specifically, it is a rare form of ependymal tumor. They are usually in middle aged people. Earlier, they were called subependymal astrocytomas
Astrocytomas are a type of brain tumor. They originate in a particular kind of glial cells, star-shaped brain cells in the cerebrum called astrocytes. This type of tumor does not usually spread outside the brain and spinal cord and it does not usu ...
.
The prognosis
Prognosis (Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain stabl ...
for a subependymoma is better than for most ependymal tumors, and it is considered a grade I tumor in the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...
(WHO) classification.
They are classically found within 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 ...
, typically have a well demarcated interface to normal tissue and do not usually extend into the brain parenchyma
Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms.
Etymology
The term ''parenchyma'' is New Latin from the word π ...
, like ependymoma
An ependymoma is a tumor that arises from the ependyma, a tissue of the central nervous system. Usually, in pediatric cases the location is intracranial, while in adults it is spinal. The common location of intracranial ependymomas is the fourth ...
s often do.
Symptoms and signs
Patients are often asymptomatic, and are incidentally diagnosed. Larger tumours are often with increased intracranial pressure.
Pathology
These tumours are small, no more than two centimeters across, coming from the ependyma. The best way to distinguish it from a subependymal giant cell astrocytoma is the size.Diagnosis
The diagnosis is based on tissue, e.g. abiopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a d ...
. Histologically
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...
subependymomas consistent of microcystic spaces and bland appearing cells without appreciable nuclear atypia
Nuclear atypia refers to abnormal appearance of cell nuclei. It is a term used in cytopathology and histopathology. Atypical nuclei are often pleomorphic.
Nuclear atypia can be seen in reactive changes, pre-neoplastic changes and malignancy. S ...
or mitoses
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...
. The nuclei tend to form clusters.
On a CT, it often shows a less dense to equally dense mass. If it is big, it may have parts that are cystic or calcific. In 50-60% of cases, the tumor is in the fourth ventricle, while the second most common (30-40% of cases) location is the side ventricles. It is rare for it to be in the third ventricle or the central canal of the spinal cord.
Treatment
Asymptomatic cases may only need watchful waiting. If symptomatic, it can be surgically removed, and partial removal also carries an excellent prognosis.Prognosis
The outlook of a cure is extremely favorable.References
External links
{{Central nervous system tumors Brain tumor