What does subependymal refer to anatomically?

From the Guidelines

Subependymal refers to the anatomical region located immediately beneath the ependyma, which is the thin epithelial membrane lining the ventricles of the brain and the central canal of the spinal cord. This area is positioned between the ependymal layer and the underlying brain parenchyma. The subependymal zone is particularly significant as it contains neural stem cells in the adult brain, making it one of the few regions where neurogenesis continues throughout life.

Key Characteristics of Subependymal Region

• Located beneath the ependymal layer
• Contains neural stem cells
• Significant for neurogenesis in adult brain
• Derived from the germinal matrix of the fetal brain
• Site of various pathologies, including subependymal hemorrhages, subependymal nodules in tuberous sclerosis complex, and subependymal giant cell astrocytomas, as seen in studies such as 1

Clinical Relevance

The subependymal area is clinically relevant due to its association with various neurological conditions. For instance, subependymal nodules are a characteristic feature of tuberous sclerosis complex, and subependymal giant cell astrocytomas are a type of brain tumor that arises in this region, as described in 1. Understanding the anatomy and pathology of the subependymal region is essential for accurate diagnosis and treatment of these conditions.

Anatomical Significance

The subependymal zone is most prominent along the lateral walls of the lateral ventricles, and its development is closely related to the germinal matrix of the fetal brain. This region plays a crucial role in the production of neurons and glial cells during early brain development, and its abnormal development can lead to various neurological disorders, as discussed in 1.

From the Research

Anatomical Definition of Subependymal

• The term "subependymal" refers to a location beneath the ependyma, which is a thin layer of cells lining the ventricles and central canal of the spinal cord in the brain and spinal cord 2, 3.
• Subependymal giant cell astrocytomas (SEGAs) are tumors that occur in the wall of the lateral ventricle and foramen of Monro, and rarely in the third ventricle 3.
• The subependymal region is a specific area where these tumors typically arise, and they can cause obstructive hydrocephalus and other symptoms due to their location 4, 5.
• The definition of subependymal giant cell astrocytoma has been documented as a lesion at the caudothalamic groove with either a size of more than 1 cm in any direction or a subependymal lesion at any location that has shown serial growth on consecutive imaging regardless of size 3.

Associated Structures and Locations

• The foramen of Monro is a common location where subependymal giant cell astrocytomas occur, and these tumors can cause obstructive hydrocephalus and sudden death if left untreated 3, 6.
• The lateral ventricles and third ventricle are also associated with the occurrence of subependymal giant cell astrocytomas 3, 4.
• The caudothalamic groove is another specific location where these tumors can be found, and it is an important landmark for diagnosing subependymal giant cell astrocytomas 3.