The severity of anaplastic pituitary tumors is largely related to the size of the pituitary tumor and whether or not it is pressing on the surrounding tissues. If the pituitary tumor is small, it usually does not compress the pituitary tissue and surrounding tissues and is usually not serious. If the tumor is large enough to compress not only the normal pituitary tissue, but also the pituitary stalk, the optic chiasm, or surrounding tissues, serious symptoms may occur, such as headache, nausea, vomiting, vision loss, or hypopituitarism. If the pituitary stalk is compressed, it can lead to uremia. Therefore, the severity of anaplastic pituitary tumors depends on the size of the tumor and whether or not it is compressing the surrounding tissues.