Three histological types of astrocytoma

Astrocytomas are tumors composed of astrocytes. They are relatively common central brain tumors that can grow anywhere in the brain or spinal cord. Most adult astrocytomas grow in the cerebrum, while pediatric astrocytomas often grow in the cerebellum and brainstem. Astrocytomas can be divided into three subtypes histologically.

1. Fibrous type: This is the most common type and can be found in almost any part of the central nervous system, but it is mostly concentrated in the cerebral hemispheres in adults and more common in the cerebellum, brainstem and thalamus in children and adolescents. This type of fibrous brain tumor is very hard, sometimes a little elastic like rubber, with abundant blood vessels in the tumor tissue, and no proliferation of vascular endothelial cells. The interstitium may be calcified, and the adjacent cerebral cortex may be infiltrated by the tumor and become dark gray. Cysts of different sizes and shapes may form in the center of the tumor.

2. Obese cell type: This type is relatively rare, accounting for about 25% of astrocytomas. It is usually found in the cerebral hemispheres and also in the septum pellucida. The tumor grows in an infiltrative manner and grows rapidly. Small cysts may form on the surface of the tumor and the texture is soft. Obese cells observed under a microscope are enlarged, spherical or polygonal, with uniform and transparent cytoplasm and short and thick protrusions. The nucleus of the tumor is very small, the nucleolus is not obvious, the nuclear division is rare, and the cytoplasm is foamy and abundant.

3. Protoplasmic type: This is the rarest type, usually located in the temporal lobe of the brain. The invasion site of protoplasmic cancer is relatively superficial, mainly in the cerebral cortex, and the distance between the affected gyri widens and becomes flat. When it is a little more serious, the cancer can invade the white matter and develop deeply in an infiltrative manner, forming cystic tissues of varying sizes, numbers and shapes. The hemisection of the tumor is generally translucent and uniformly jelly-like.