Pituitary adenoma is a relatively common slow-growing intracranial tumor with an incidence of about 1-10/100,000 people. In the past, the incidence of pituitary adenoma was the third most common intracranial tumor. Pituitary adenomas can be divided into microadenoma (less than 1cm in diameter), macroadenoma (1-5cm) and giant adenoma (more than 5cm) according to the size of the tumor. Microadenomas mainly show symptoms and signs of endocrine disorders, while macroadenomas and giant adenomas have vision and visual field changes in addition to endocrine disorders. Meng Xiangjing, Department of Neurosurgery, Shandong Qianfo Mountain Hospital
Diagnostic points]
(A) Prolactin (PRL) adenoma is common in women, mainly manifesting as amenorrhea, overflowing breast and infertility triad; it is rare in men, whose main manifestations are impotence, hypogonadism, breast development and lactation in a few patients. Serum prolactin is significantly increased.
(B) Growth hormone (GH) adenoma in adolescent patients mainly manifests as excessive growth, called gigantism; in adult patients, it mainly manifests as acromegaly, wide face, and late stage may show hypogonadism. Serum growth hormone is increased.
(iii) Adrenocorticotropic hormone (ACTH) adenoma mainly manifests as centripetal obesity, hypertension, hirsutism, skin pigmentation and abnormal glucose metabolism, and increased serum ACTH.
(iv) Mixed adenoma tumor tissue contains two or more tumor components, especially PRL-GH mixed adenoma is the most common.
(e) Non-secretory adenoma This kind of pituitary tumor cells have no secretory function and do not show symptoms of endocrine hyperfunction. The main symptom is that the tumor increases in size and compresses the optic cross and pituitary gland, resulting in changes in visual acuity and visual field and symptoms of hypopituitary function.
Auxiliary examination
(a) CT scan is mostly a round, smooth, isodense or slightly dense mass with clear borders, and there may be necrosis or cystic hypodense area in the center. However, the detection rate of microadenoma is only 30%.
(b) MRI imaging of microadenoma shows internal focal signal abnormalities, superior pituitary rim upward convexity, pituitary stalk displacement, and saddle subdepression or slight subluxation. Macroadenomas show loss of normal pituitary signal, and the tumor may be solid, cystic, necrotic, or hemorrhagic. The tumor may grow upward to occupy the suprasellar pool, elevate the optic cross, or enter the third ventricle and lateral ventricle, laterally invade the cavernous sinus, encircle or compress the internal carotid artery, and protrude downward into the pterygoid sinus.
(C) Most of the microadenomas are normal, and a few of them may show thinning of the saddle base; most of the large adenomas and giant adenomas show changes such as enlargement of the pterygoid saddle and bone resorption.
(d) Cerebral angiography shows orthopantomogram of large adenoma and giant adenoma shows solitary upward shift of horizontal segment of anterior cerebral artery and outward shift of siphon segment of internal carotid artery. Microadenomas are mostly unchanged.
Treatment points
（Although bromocriptine can improve the endocrine symptoms of some patients, long-term medication is needed; radiotherapy is mostly used as postoperative adjuvant treatment, and the cure rate of radiotherapy alone is very low.
(2) Most pituitary adenomas, especially those with visual acuity and visual field changes, should be treated by surgery.
(c) Functional pituitary adenoma can be removed by microsurgery through the pterygoid sinus approach at the microadenoma stage, and most of them can be cured.
(d) If pituitary stroke occurs, emergency surgery should be performed.
(5) For pituitary macroadenomas and giant adenomas with extensive involvement, especially when hypopituitarism and hypothalamic symptoms appear, surgery is poorly tolerated and direct and indirect damage to hypothalamus and other structures should be avoided as much as possible during surgery.
【Surgical methods】.
(a) The transoral nasal butterfly approach is suitable for resection of microadenoma, large adenoma in the saddle and most of the large adenoma and giant adenoma developing to the saddle. The surgery is less invasive and the postoperative reaction is mild. However, there is more intraoperative bleeding, easy to be infected and inconvenient to eat after surgery.
(b) Single nostril approach is a modification of the transoral nasal butterfly approach, with the same indications as the transoral nasal butterfly approach.
(c) Inferior frontal approach, which is suitable for resection of large adenoma in the saddle and large adenoma developing to the saddle and giant pituitary adenoma.
(iv) Pterygopoint approach. It is suitable for resection of intra-saddle macroadenoma, supra-saddle development macroadenoma and giant adenoma, especially the tumor that develops more to one side. Generally, the right side approach is adopted, but the side with more development is also preferred. The surgery is performed along the lateral fissure to approach the saddle area, which is less damaging to the brain tissue.
Postoperative treatment
(a) Adrenocorticotropic hormone treatment, such as flumethasone 5-10mg/d, reduce the dosage after 3-5 days postoperatively, and stop or use maintenance dosage 7-10 days postoperatively.
(b) Individuals with urogynecology should be treated with dihydrocortisone, carbamazepine, long-acting urogynecology or posterior pituitary hormone.
(c) Pituitary adenomas that cannot be completely excised should be treated with radiation therapy or chemotherapy after surgery.
Before and after pituitary tumor surgery