Craniopharyngioma and pituitary tumor are the two most common benign intracranial saddle area tumors, and it is sometimes difficult to distinguish them clearly before surgery. In order to facilitate the readers to grasp certain knowledge in this regard, we would like to give some brief overviews on the differentiation of the two, hoping to be helpful to you. 1.What is the difference between the symptoms of craniopharyngioma and pituitary tumor? The symptoms of craniopharyngioma and pituitary tumor have many similarities, but because craniopharyngioma is a congenital disease, it is more common in children, while pituitary tumors are more common in adults and very rarely in children. Overall the incidence of pituitary tumors is significantly higher than that of craniopharyngioma. The main manifestation of craniopharyngioma in children is delayed growth and sexual maturation, while the main manifestation of craniopharyngioma in adults is hypopituitarism, which manifests as dysfunction in men and weakness and loss of appetite in women. Patients with craniopharyngioma often have symptoms of excessive drinking and urination and visual impairment; while patients with pituitary adenoma with different endocrine functions may show symptoms of increased secretion of related pituitary hormones, such as: (1) growth hormone type showing gradually enlarged hands and feet, thickened nose and lips; (2) prolactin type showing sparse hair and delicate skin in men and scanty menstruation or amenorrhea and lactation in women; (3) adrenocorticotropic hormone type showing full moon face, buffalo back and purple skin on the abdominal back. (3) Pro-adrenocorticotropic hormone type manifests as full moon face, buffalo back, and purple skin discoloration on the abdominal back. Some non-functional pituitary tumors only appear when the tumor grows to a certain size, such as visual impairment and headache. 2.What is the difference between the two tumors in terms of growth site? Most craniopharyngiomas are located above the saddle diaphragm, and giant craniopharyngiomas often invade the lower part of the optic thalamus and even protrude into the third ventricle and lateral ventricles, while a few small craniopharyngiomas are located in the saddle or above and below the saddle diaphragm. Large adenomas can break through the saddle diaphragm and grow up the saddle or break through the saddle base and enter the cavity of the pterygoid sinus or even the septal sinus, and invasive pituitary adenomas can invade both cavernous sinuses and even encircle the internal carotid artery. 3.What are the differences in the positive indicators of blood biochemical examination between the two? Craniopharyngioma itself has no endocrine function, but due to the pressure of tumor on pituitary gland and important structures such as pituitary stalk and hypothalamus, it is often accompanied by hypopituitary function and a number of hormones such as thyroid hormone, growth hormone, cortisol and gonadotropin, etc. A few of them have electrolyte disorders such as sodium and potassium due to polydipsia and polyuria; while different types of functional pituitary adenomas may have elevated growth hormone, prolactin and cortisol. Some growth hormone adenomas may be complicated by diabetes mellitus, resulting in elevated blood glucose and positive urine glucose, and a few non-functional pituitary adenomas may have low levels of several hormones due to hypopituitarism. How to distinguish these two types of tumors? Can skull base CT distinguish between these two tumors? The differentiation between these two tumors mainly relies on cranial CT and MRI examination. In contrast, most craniopharyngiomas show calcification, cystic changes are common, and intra-tumoral bleeding rarely occurs, while craniopharyngiomas can be seen as normal pituitary gland on enhanced MRI. 5.What tests are needed to diagnose craniopharyngioma? The following tests are usually required for the diagnosis of craniopharyngioma: cranial CT, cranial MRI with plain and enhanced scans, pituitary endocrine function and blood biochemical examination, visual field and fundus examination, etc. If cortisol is extremely low, cortisol will be rechecked after a period of replacement therapy.