It is caused by congenital abnormalities or surgery that causes the hole in the middle of the septum to be too large, resulting in the herniation of the arachnoid membrane of the suprasellar pool into the pituitary fossa through the enlarged saddle diaphragm hole, resulting in a cystic lesion containing cerebrospinal fluid. Usually, vacuolation of the saddle does not cause any symptoms and is not detected by the patient, but is mostly discovered accidentally during cranial CT examinations for head trauma. Only when the cyst is large enough to compress the pituitary gland or the optic nerve, resulting in hypopituitarism or vision loss, surgery is required. Surgery is usually performed through a minimally invasive transnasal procedure to release the cystic fluid from the saddle and repair the enlarged saddle diaphragm hole.