With the increasing level of pituitary tumor detection, the incidence of pituitary tumors has been increasing year by year. According to the American epidemiological survey, the incidence of pituitary tumors is 10/100,000. Foreign studies have shown that the detection rate of pituitary tumors is 16% in a random sample of 100 normal people who underwent MRI of the saddle area, indicating that the detection rate of pituitary tumors is very high, only that most patients do not show clinical symptoms.
Pituitary tumors usually occur during young adulthood and often affect the patient’s growth and development, reproductive function, learning and working ability. The clinical manifestations of pituitary tumors vary widely, and the departments where patients are first seen can be relatively scattered, so patients are often referred to multiple departments and are not properly diagnosed and treated for a long time, thus delaying their condition and causing unnecessary mental and physical stress to patients.
Classification
Pituitary tumors can be classified according to the size of the tumor and the function of hormone secretion. According to the size of the tumor, pituitary tumors are divided into pituitary microadenomas (tumors less than 1 cm in diameter) and pituitary tumors (tumors greater than or equal to 1 cm in diameter). According to the secretion of hormones, it can be further classified into secretory pituitary tumor and non-functional pituitary tumor. The size of pituitary tumor is closely related to the prognosis of treatment. Most non-functional pituitary tumors do not require treatment and can be followed clinically for a long time if there is no corresponding change in pituitary function. If the corresponding clinical symptoms appear during the follow-up, surgery may be considered.
Clinical symptoms
1. Clinical manifestations caused by increased secretion of hormones by pituitary tumors. The clinical manifestations differ depending on the type of hormone secretion.
1. Prolactin-type pituitary tumor. Female patients mainly present with amenorrhea, lactation and infertility. Male patients mainly present with hypogonadism, decreased libido, impotence and infertility.
2. Growth hormone-type pituitary tumor. Adolescent patients mainly manifest as gigantism, and adults manifest as acromegaly, facial changes, coarsening of hands and feet (increased shoe size), excessive sweating, bone and joint lesions, carpal tunnel syndrome, swelling of soft tissues and joints of hands and feet, increased blood pressure, increased blood sugar, coronary heart disease, and tumors of thyroid gland and colon, etc.
3.Adrenocorticotropic hormone (ACTH)-type pituitary tumor. Patients show centripetal obesity, full-moon face, acne, hirsutism, purple lines (purple-red skin lines on the body).
4. Thyrotropic hormone (TSH) type pituitary tumor. Patients show symptoms of hypermetabolism, with fear of heat, excessive sweating, weight loss, and heartburn.
5. Other pituitary tumors are FSH and LH. Female patients mainly present with menstrual disorders and infertility, while male patients mainly present with hypogonadism and infertility. Hormone-secreting tumors can occur alone or be mixed tumors with increased secretion of two or more hormones, and the clinical manifestations also have corresponding mixed symptoms.
2.Clinical manifestations of pituitary tumors with reduced hormone secretion caused by compression of normal pituitary gland.
1. Hypoadrenocorticism can be manifested as decreased appetite, weakness, emaciation, hypotension, hypoglycemia, easy to catch cold, etc.
2, hypothyroidism can be manifested as fear of cold, appetite loss, rough skin, hair loss, constipation, etc. In children, it can manifest as dementia, growth retardation, etc.
3. Hypogonadism can be manifested as infertility, decreased libido, menstrual disorders or even amenorrhea in women and impotence in men.
4.Decreased secretion of growth hormone can be manifested as short stature in children, and in adults, it can be manifested as concentration of body fat in the abdomen, muscle relaxation and atrophy, aging, decreased self-awareness, osteoporosis, decreased resistance, and reduced sexual function, etc.
3.Symptoms of pressure on peripituitary structures: if the tumor grows to the saddle and presses on the visual cross, it will manifest as vision loss, visual field defect, etc. Patients usually complain of frequent bruises, etc. If the tumor invades the cavernous sinus around the pituitary gland, it will show symptoms of nerve pressure such as ptosis, pupil enlargement and other clinical manifestations.
4.Pituitary stroke: During the growth of tumor, due to poor blood supply or abnormal growth of tumor blood vessels, under certain inducements, tumor bleeding and necrosis of tumor tissue will occur. If the tumor is completely bleeding and necrosis and the tumor envelope is ruptured, there will be severe headache, nausea and vomiting or even blindness and coma, which needs emergency surgical treatment. Most strokes of pituitary tumors present as incomplete or partial pituitary strokes, which can be mild headache, nausea and vomiting with general discomfort and do not require special treatment. Patients’ symptoms will resolve on their own within a few weeks, and clinical symptoms of certain hormone-secreting tumors are reduced.
Diagnosis
The diagnosis of pituitary tumor is based on clinical symptoms, physical signs, pituitary hormone tests and imaging examinations.
In terms of pituitary hormone testing, it should be noted that the secretion of GH, ACTH and PRL has a distinct circadian rhythm, and they are all stress hormones. The clinical time for GH and ACTH should be 8AM (fasting), and the blood should be taken at rest for more than half an hour in a quiet state before taking blood. The measurement of PRL should be taken between 10AM and 2PM, so that the measured value can reflect the patient’s serum PRL level under non-stressful conditions.
For imaging of pituitary tumors, magnetic resonance imaging (MRI) of the saddle area has the highest detection rate of pituitary tumors. Dynamic enhancement of the pituitary gland can detect pituitary microadenomas as small as 2-3 mm in diameter. Enhanced CT imaging of the saddle area is good for partial visualization of pituitary macroadenomas and can provide insight into the degree of destruction of the saddle base bone and the degree of pterygoid sinus pneumatization.
The diagnosis of pituitary tumor is not difficult to determine by detailed clinical interview, physical examination, pituitary hormone measurement and imaging.
Treatment
Treatment of pituitary tumors consists of three main methods: surgery, medication and radiation therapy. Each method has its own advantages and disadvantages, and individualized treatment plans should be developed based on the size of the pituitary tumor, hormone secretion, complications and co-morbidities, the patient’s age, whether the patient has fertility requirements, and the patient’s financial situation.
Surgical treatment can be divided into open pituitary tumor resection and transnasal butterfly pituitary tumor resection, and transnasal butterfly surgery can be divided into microscopic transnasal septal surgery and endoscopic transnasal butterfly surgery, endoscopic surgery is less traumatic and is currently used in most large treatment centers.
The drug treatment of hormone-secreting pituitary tumors has made great progress in recent years. For pituitary prolactin-secreting tumors, the current view is that more than 90% of patients (either microadenomas or macroadenomas) can have their PRL levels controlled with the dopamine agonist bromocriptine, which reduces the size of the tumor. Only those patients with prolactinoma who are allergic or drug intolerant to this class of drugs and whose acute symptoms due to tumor compression require emergency surgical decompression opt for surgical treatment. During treatment with bromocriptine, the dose of bromocriptine should be gradually increased until after the serum PRL level drops to normal, and the dose is adjusted for long-term maintenance therapy.
For growth hormone-secreting pituitary tumors, the main application is the use of growth inhibitor analogs. The long-acting formulation of growth inhibitor analogs, octreotide, has led to a significant improvement in patient compliance. The preoperative application of these drugs 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. Additional indications for the use of growth inhibitor analogs in GH-secreting tumors include: postoperative residual patients, and transitional treatment of patients whose GH has not been reduced to normal after radiotherapy. The application of agents such as octreotide offers the opportunity to prepare treatment before surgery for those patients who are unable to tolerate anesthesia due to concomitant heart failure, apnea, poorly controlled hyperglycemia, and hypertension. Growth-suppressing hormone analogs have also been used for thyrotropin-secreting tumors with satisfactory therapeutic results.
Pituitary tumors are adenomas and are inherently less sensitive to radiotherapy. Nearly 70-80% of patients develop hypopituitarism after radiotherapy, which reduces the quality of life of patients, so radiotherapy is only indicated for patients with surgical residuals, who cannot tolerate surgery, who are insensitive to drugs, and who have co-morbidities that cannot be treated with surgery or drugs.
Lifetime follow-up
All patients treated for pituitary tumors should be followed up for life. Pituitary function is reviewed regularly (every 3-6 months) after surgery, and MRI of the saddle area is reviewed if necessary to monitor tumor recurrence and growth. The level of anterior pituitary hormone secretion varies with age, so one year after surgery, pituitary hormone measurement should be done annually according to the patient’s specific condition to replace the already diminished pituitary hormone according to the situation.
In summary, pituitary tumors are a group of benign neuroendocrine neoplastic diseases that can be effectively controlled by various methods of treatment such as surgery, drugs and radiotherapy. In view of the specificity of their growth sites, while diagnosing and treating patients, the different characteristics of the nature of pituitary tumors should be addressed, and in close cooperation with multi-disciplinary departments (endocrinology, neurosurgery, radiotherapy, ophthalmology, radiology imaging, etc.) In addition, a personalized treatment plan should be formulated according to the different needs of patients. Ultimately, the patient’s tumor can be removed, the recurrence of the tumor can be avoided during the lifelong follow-up, the pituitary function can be preserved as much as possible, the elevated secretory hormone can be reduced to the normal range, and the reduced pituitary hormone can be replaced to the age-matched normal range to improve the patient’s quality of life and prolong the patient’s life expectancy.