1. Overview.
Gliomas arise from the supporting tissues of the nervous system and are ectodermal tumors.
Many gliomas have tumor cells similar to mature or immature glial cells.
2.Typing.
(1) Astrocytoma
① Occurrence.
It occurs from astrocytes and accounts for more than half of the gliomas.
They occur in the cerebral hemispheres in adults and in the cerebellum in children. Others such as thalamus, brainstem and spinal cord can occur.
Astrocytomas can be divided into two types: fibrous and protoplasmic.
The tumor grows infiltratively in the brain and varies in size. It can invade one or more lobes of the brain and even invade the contralateral cerebral hemisphere via the corpus callosum.
② Gross morphology.
Fibrous astrocytomas are relatively hard and tough.
Protoplasmic astrocytomas are soft and often have cystic changes.
Intratumoral hemorrhage and necrosis are relatively rare.
(iii) Microscopic morphology.
The tumor tissue is composed of more maturely differentiated astrocytes.
Fibrous astrocytomas are rich in glial fibers.
Protoplasmic astrocytomas are rich in cytoplasm.
If the astrocytes are more dense, the cells are heterogeneous, and filiform nuclear schizophrenic images, hyperplasia of vascular endothelial cells and ependymal cells, small focal hemorrhages and necrosis are seen, the tumor is called astroblastoma, or poorly differentiated astrocytoma.
(2) Glioblastoma multiforme
(1) Occurrence.
It is a relatively common malignant glioma in adults.
The incidence is second only to astrocytoma.
It occurs mostly in the cerebral hemispheres and rarely in the cerebellum.
② Gross morphology.
Tumor infiltration is relatively large and can invade several brain lobes or the contralateral cerebral hemisphere via the corpus callosum.
The tumor is soft, grayish-red in color, and often shows large areas of hemorrhage and necrosis.
The peritumor tissues are significantly edematous and even liquefied, showing pseudo-demarcation.
In fact, the infiltration of tumor cells is much more extensive than what is seen with the naked eye.
(iii) Microscopic morphology.
The tumor cells are immaturely differentiated, pleomorphic, heterogeneous, with more nuclear division images, often with significant proliferation of mononuclear and multinucleated tumor giant vascular endothelial cells and ependymal cells, thrombosis in the vascular lumen, scattered large areas of hemorrhage and necrosis and poorly differentiated astroblastoma without clarity.
(3) Oligodendroglial cell tumor and oligodendroglioblastoma
(1) Occurrence.
Patients with oligodendroglioma are mostly middle-aged and can also be seen in children, mainly in the white matter of the cerebral hemispheres.
② Gross morphology.
The tumor is soft, gray-red, poorly defined, often with calcification and cystic changes.
③Microscopic morphology.
The tumor cell morphology is relatively consistent, the nucleus is round, deeply stained, the perinuclear cytoplasm appears blank due to edema, there is little interstitium, common foci of calcification and cyst formation If the tumor cell size, morphology, nuclear staining is inconsistent and giant tumor cells with nuclear division image, vascular endothelial cell hyperplasia with hemorrhage and necrosis, it is called oligodendroglioblastoma.
(4) Ventricular meningioma and ventriculoblastoma
(1) Occurrence
They are often associated with the ventricular wall and central canal, and are found in the fourth ventricle, lateral ventricle and spinal cord in young children and young adults.
② Gross morphology.
The tumor is gray-red, soft, and mostly nodular protruding in the ventricular cavity or located in the brain or spinal cord parenchyma.
③Microscopic morphology.
Ventricular meningioma is divided into four types: epithelial type, papillary type, papillary mucinous type and cellular type.
(5) Mixed glioma
The tumor is composed of two or more glioma types, each with a significant fraction.
This type of glioma is most commonly seen in pediatric patients, and can be seen in the cerebellum and brain with no difference in morphology from the general glioma.
(6) Medulloblastoma
①Occurrence
It is a more common malignant tumor in pediatric skull.
It mainly occurs in the cerebellar earth, and may protrude into the fourth ventricle or invade the surrounding tissues.
It often spreads along the cerebrospinal fluid in an implantation manner.
② Gross morphology.
The tumor is purplish red, mucous jelly-like, with indistinct boundary between brain parenchyma, and hemorrhagic necrosis is rare.
③Microscopic morphology.
Tumor cells are dense, with little interstitium, small tumor cells, garden-shaped or oval nuclei, deep staining, little cytoplasm, nuclear fission images are often seen, and cells are often arranged in pseudo-chrysanthemum shape.
If the tumor invades the soft membrane, it is often accompanied by the obvious proliferation of fibrous connective tissue.