1 CH 14: HUMAN BRAIN DMG CAUSES OF BRAIN DMG TUMORS (mass of new and abnormal tissue , not physiologically beneficial to surrounding structures) Also called neoplasm (new tissue) also described as space-occupying lesions (foreign objects and cause dmg to CNS by putting pressure on it and occupying space) Tumors differ in terms of what type of cells give rise to tumor, how rapidly they grow, whether they infiltrate and destroy surrounding neural tissue or remain relatively encapsulated and how likely they are to recur if removed. Benign tumor not likely to recur, malignant ones are more likely. 4 types of brain tumors: ones that originate from glial cells, meninges, nervous tissue, or other parts of body already infected with tumor. TUMORS ARISING FROM GLIAL CELLS gliomas most common tumor in brain arise from glial cells. Two main types: Astrocytomas (arise from growth of astrocytes dont grow quickly, rarely malignant. Some are well encapsulated so dmg they cause tends to come from compression of surrounding tissue, meanwhile others infiltrate surrounding neural tissue (when surgical treatment is not practical, chemotherapy is typically used) Gliobastoma is the 2ndtype opposite of astrocytomas grow fast and highly malignant instead of being encapsulated they tend to infiltrate surrounding tissue, making them hard to excise surgically wout getting rid of good surrounding neural tissue. (so chemo is usually the method to treat) Medulloblastoma (is less common type of glioma) very malignant infiltrating tumor tend to form around cerebellum and brainstem early in life. Prognosis is poor, chemo is most attractive TUMORS ARISING FROM MENINGES Meningiomas tumors that grow out of and remain attached to the meninges most of them grow out of dura mater forming an ovoid shape. Harmful effects tend to be from pressure to site of tumor as well as sites distal to tumor most of them are benign, some are malignant. Surgery is best treatment bc of location on surface of brain. METASTATIC TUMORS (or metastases) 2ndary tumors that form from migrated tumor tissue. Primary site could be lungs, breast, uterus or kidney or maybe CNS but less common. Simple metastatic tumor occur when only 1 tumor forms at 1 site. In most cases there are multiple metastatic tumors usually spreading from lungs to CNS.