What Are Oligodendrocytes?

Oligodendrocytes are distributed in the central nervous system. It is smaller than astrocytes, with short and few neurites. The nucleus is round, small and dense. The electron density of cytoplasm is high under electron microscope, and it mainly contains mitochondria, ribosomes and microtubules. In the gray matter, oligodendrocytes are mainly located near the perinuclear body; in the white matter, they exist side by side between myelinated nerve fibers and form a myelin sheath. Tissue culture showed active oligodendrocytes.

Oligodendrocytes are distributed in the central nervous system. It is smaller than astrocytes, with short and few neurites. The nucleus is round, small and dense. The electron density of cytoplasm is high under electron microscope, which mainly contains mitochondria, ribosomes and microtubules. In the gray matter, oligodendrocytes are mainly located near the perinuclear body; in the white matter, they exist side by side between myelinated nerve fibers and form a myelin sheath. Tissue culture showed active oligodendrocytes.

Chinese name

Oligodendrocyte

Foreign name

oligodendrocyte

Alias

Oligodendrocyte

Distribution

Central Nervous System

Features

Assist excitement transmission and protect neurons

Physiological functions of oligodendrocytes :

The main functions of oligodendrocytes are to surround axons in the central nervous system, form an insulating myelin sheath structure, assist in the jump-type efficient transmission of bioelectrical signals, and maintain and protect the normal functions of neurons. Its abnormalities not only cause demyelination of the central nervous system, but also cause neuronal damage or mental illness, and can even cause brain tumors.

Oligodendrocyte tumors:

(I) Introduction :

Oligodendrocyte tumors include oligodendroglioma and anaplasticoligodendroglioma. The WHO malignancy of oligodendroglioma is classified as Grade II, and the malignancy of WHO as anaplastic oligodendroglioma is classified as Grade III. Because oligodendroglioma often contains other glial components, it appears as mixed gliomas. Therefore, simple or true oligodendrocyte tumors are rare.

(B) Origin:

Tumors originate from oligodendrocytes in the white matter of the brain. Oligodendroglioma is mainly found in adults, and the age of onset is 35 to 40 years. The adult to child ratio is 8: 1. There are slightly more men than women. Tumors grow slowly and may have a history of 3 to 5 years before diagnosis. Patients often have focal epilepsy as the first symptom. Other symptoms vary depending on the tumor site. Tumors often occur in the cerebral hemisphere, with the frontal lobe most common, followed by the parietal lobe, temporal lobe, and occipital lobe. Tumors are located in the white matter of the brain and can spread to the cerebral cortex. A few can involve the ventricles, but they are rare in the ventricles.

(Three) fine structure:

Pathologically, the tumor has no envelope, but it has a clear state and is located in the white matter of the brain, which can expand to the cortex and pia mater. Very few oligodendrogliomas can also have an unclear state, showing diffuse invasive growth. The texture of the tumor is soft and gel-like, and obvious cystic changes, bleeding and necrosis are rare in the tumor. Intratumoral calcification is common and obvious.

During plain CT scans, tumors usually show a mixed density of calcification, and the incidence of calcification can be as high as 70% to 90%. The uncalcified part often shows the same density or slightly higher density, and a few can also have the same density and low density. The typical manifestation is that calcified mixed-density tumors in the cerebral hemisphere spread to the surrounding cortex. The skull can be eroded. Significant bleeding within the tumor is rare. Edema around the tumor is usually mild. Most of the enhanced CT scans have mild to moderate enhancement. MRT ₁ weighted maps often show low and equal promiscuous signals, and T ₂ weighted maps show high signals. Enhanced MR scans are mostly patchy mild to moderately enhanced. The tumor realm is clear. The placeholder effect is relatively light, but the placeholder effect can be more obvious when the tumor is larger. MR is less sensitive than CT in the display of tumor calcification.

Most scholars believe that oligodendroglioma and benign astrocytoma are difficult to distinguish in imaging, and the difference is only pathological. However, the following three points suggest oligodendroglioma. Calcification is more common in oligodendrocyte tumors. Calcification can be located at the center or edge of the tumor, or at the same time as the center edge. Although benign astrocytoma can also appear calcification, calcification of oligodendrocyte gliomas is often more obvious. Calcification usually starts from small blood vessels, and calcified bodies are deposited along the blood vessel wall and surrounding tumor tissue. Banded or brain-like. Oligodendrocyte tumors often extend to the cerebral cortex, which can involve the meninges and erode the skull, while astrocytomas are located deeper, mostly in the white matter region of the hemisphere, and rarely invade the cortical surface. Therefore, when the tumor is located near the brain surface, especially when there is a skull change, the possibility of oligodendrocyte tumor should be considered. Because oligodendroglioma cells are densely packed, the non-calcified part is mostly of the same density or slightly higher density on CT, while benign astrocytoma tumor cells are loose and mostly low density.