Pituitary adenomas are a group of tumors that occur from the anterior and posterior pituitary lobes and the epithelial remnant cells of the craniopharyngeal canal and account for 10% to 15% of central nervous system tumors. The vast majority of pituitary adenomas are benign tumors. Among them, PRL tumors are the most common accounting for about 50-55%, followed by GH tumors in 20-23%, ACTH tumors in 5-8%, and TSH tumors and LH/FSH tumors are less common. Non-functioning pituitary adenomas account for 20-25% of cases. Recently, several patients with pituitary tumors have been treated irregularly, resulting in hypopituitarism and lifelong reliance on hormone supplementation. The standardized diagnosis and treatment process of pituitary adenoma is described as follows.
Step 1: Clear diagnosis in endocrinology
1. Clarify whether there is occupancy in the pituitary gland.
MRI examination is the most important tool to diagnose pituitary tumor, which can clearly show the size, morphology, location and relationship with surrounding structures of the tumor.
2.Define whether pituitary tumor secretes hormones and affects pituitary and target gland function: Check pituitary hormones, including PRLACTHTSHFSHLHGH, and evaluate target gland hormones, including adrenocorticotropic hormone, thyroid hormone (FT3FT4), sex hormone (E2PT), IGF-1, etc.
3. To clarify whether there is local compression of pituitary tumor: assessment of visual field defects, testing of visual acuity, etc.
4. Differential diagnosis of pituitary tumor
(1) Tumor: craniopharyngioma, saddle node meningioma, Raschke’s cleft cyst, germ cell tumor, optic cross glioma, epithelioid cyst.
(2) Inflammation: pituitary abscess, eosinophilic granuloma, lymphocytic pituitary inflammation, mycobacterial inflammation, tuberculous meningitis.
(3) Hyperplasia.
(1) Physiological: during pubertal development, pregnancy and lactation.
(2) Pharmacological: Sedative and sleeping drugs for psychiatric disorders are the most obvious. Some proprietary Chinese medicines such as Six Bit Dihuang Pills can also cause hyperplasia of pituitary tissue and a significant increase in serum PRL.
(3) Compensatory: hypothyroidism and hypoadrenocortical feedback cause pituitary hyperplasia. In particular, pituitary hyperplasia caused by hypothyroidism disappears quickly when thyroxine is supplemented.
(4) Pathological: unexplained factors cause hyperplasia of pituitary tissue, which partially transforms into tumor.
(4) Others: Intrasellar aneurysm, arachnoid cyst, primary vacuolated saddle, retrobulbar optic neuritis.
Step 2: Treatment
The treatment of pituitary tumor mainly includes surgery, medicine and radiation therapy. Individualized treatment plans need to be developed based on the size of the patient’s pituitary tumor, hormone secretion, complications and co-morbidities, the patient’s age, whether he or she has fertility requirements, and the patient’s financial situation. Treatment of pituitary tumors is a comprehensive treatment process with multi-disciplinary collaboration.
1.Pharmacological treatment
(1) For pituitary prolactin-secreting tumors, more than 90% of patients (either microadenomas or macroadenomas) can be treated with dopamine agonists (short-acting agents bromocriptine, long-acting agents cabergoline) to control PRL levels and reduce the size of the tumor. Surgery is an option only for patients with prolactinomas who are allergic or intolerant to this class of drugs, who have acute symptoms due to tumor compression that require emergency surgical decompression, or for patients who do not wish to undergo surgical treatment.
(2) Treatment goals for patients with growth hormone-secreting tumors: eliminate tumors, reduce tumor recurrence, GH attainment, relieve clinical symptoms, preserve pituitary function as much as possible, improve patients’ quality of life, and prolong patients’ life expectancy. Preoperative application of growth inhibitor analogues such as long-acting octreotide and somatuline can rapidly reduce the patient’s serum GH level, alleviate the patient’s symptoms, reduce the size of the tumor, and create good preoperative conditions for complete surgical removal of the tumor. Patients with GH tumor whose GH and IGF-1 levels are still elevated after surgery should be given octreotide or dopamine agonists as adjuvant therapy; for those who have poor results with drug therapy, radiation therapy can be considered.
(3) ACTH tumors are also treated with ketoconazole or other adrenal corticosteroid synthase inhibitors to inhibit the excessive production of cortisol and to relieve clinical symptoms.
2.Radiotherapy
Pituitary tumor is an adenoma, and its sensitivity to radiotherapy is poor. 70%-80% of patients have reduced pituitary function after radiotherapy, which reduces the quality of life of patients, so radiotherapy is only suitable for patients who have residual surgery, cannot tolerate surgery, are not sensitive to drugs, and have co-morbidities that cannot be treated with surgery or drugs.
3.Surgical treatment
Currently, surgery is preferred for most GH tumors, ACTH tumors, TSH tumors and non-functional macroadenomas. Surgical methods include transsphenoidal sinus, craniotomy and gamma knife.
Step 3: If surgery is needed, a neurosurgeon will consult with the patient to determine the surgical plan and perform the surgery.
Step 4: Postoperative pathology is performed with routine and hormonal immunohistochemical staining to clarify the diagnosis.
Step 5: After surgery, return to the endocrinology department to assess pituitary function, determine whether relevant hormone replacement therapy is needed, and follow up with regular review.
Special reminders.
1. Drug therapy is preferred for pituitary prolactin-secreting tumors.
2. Patients with pituitary tumors and hyperprolactinemia need to check thyroid function to exclude hypothyroidism. Hypothyroidism can cause pituitary hyperplasia and elevated prolactin. When supplemented with thyroxine, pituitary hyperplasia disappears quickly, so please do not operate for treatment.