I often hear that someone has a cavernous hemangioma in his brain. So is cavernous hemangioma a real tumor? Does it grow like glioma or meningioma? A cavernous hemangioma is actually a malformation of a blood vessel. During surgery, you can see that there are malformed veins in the cavernous hemangioma, and these veins have immature walls and bleed easily. These venous malformations are congenital. So, why are the venous malformations called tumors? Because, after these malformed veins bleed, the clots become fibrous and mix with the malformed veins to form a spherical tumor, so that the tumor-like mass is seen on both film and surgery, and has a certain elastic texture, which is how cavernous hemangioma gets its name. Although they are called tumors, they are essentially a mass of venous malformations. Although spongiform hemangiomas are not true tumors, they do grow. However, the nature of this growth is completely different from that of gliomas, which are caused by the division of tumor cells resulting in an increase in tumor size. In contrast, cavernous hemangioma does not contain tumor cells, but grows due to repeated bleeding from the venous malformation, with each bleeding clot not completely absorbed to form new fibrosis, which is deposited repeatedly like sediment, resulting in a larger and larger mass encircling the malformed venous mass. Thus, cavernous hemangioma can “grow” as large as a real tumor. Once you understand cavernous hemangioma, you can see that it is not a scary disease. Intracranial cavernous hemangiomas are generally treated well and are less likely to recur after surgical removal.