Benign and malignant tumors of the pituitary gland

Disease Description (Causes and Symptoms)

• Summary of definition: The pituitary gland is the central endocrine organ connected to the hypothalamus that regulates hormone secretion in the body. Tumors arising in the pituitary gland (mostly adenomas) account for approximately 10–15% of all intracranial tumors, and most are benign (adenomas). Primary malignant pituitary cancer is extremely rare (except for metastatic or invasive lesions).
• Causes/pathophysiology: The exact cause is unknown, but hypothalamic dysfunction or abnormalities in pituitary cells have been proposed as possible mechanisms. Tumors cause symptoms through hormone hypersecretion (functional adenomas) or compression of surrounding structures due to tumor size (nonfunctional macroadenomas). Microadenomas (<10 mm) can also cause hormonal symptoms, while macroadenomas (≥10 mm) can cause optic nerve compression, headaches, and other symptoms.
• Main symptoms
  • Related to hormone hypersecretion: Excess prolactin → galactorrhea, amenorrhea and infertility, decreased libido, vaginal dryness (women), and hypogonadism (men and women). Excess growth hormone → gigantism/acromegaly. Excess ACTH → Cushing syndrome, etc.
  • Related to compression (mass effect): Headaches, visual field defects (mainly bitemporal hemianopia/loss of the outer visual fields), eye-movement disorders, etc.
  • Consequences of reduced function: Panhypopituitarism (deficiency of multiple hormones), diabetes insipidus (abnormal ADH), etc.
  • Other: Increased risk of bone loss and osteoporosis with long-term hyperprolactinemia.
• Diagnostic clues (summary)
  • Imaging: Dynamic brain MRI (focused imaging of the sella turcica) is essential. CT/skull X-rays may be used as supplementary tests.
  • Blood tests: Tests of relevant hormones (prolactin, GH/IGF-1, ACTH/cortisol, TSH/FT4, LH/FSH, etc.). Example of a clinical criterion: If the tumor is ≥1 cm and serum prolactin is ≥200 ng/mL, a prolactinoma is highly likely.
  • Visual field testing is required to identify visual field defects.

Treatment Methods and Precautions

• Treatment principles: Treatment is determined according to the tumor’s function (whether it secretes hormones), size (microadenoma/macroadenoma), symptoms (visual field defects and neurological abnormalities), and the patient’s age and pregnancy status. A multidisciplinary approach (endocrinology, neurosurgery, and radiation oncology) is recommended.
• Drug treatment
  • Prolactinoma: Dopamine agonists (first-line drug treatment) — cabergoline (preferred), bromocriptine. Effects: normalization of prolactin levels and tumor shrinkage.
  • Growth hormone-secreting adenoma (acromegaly): Somatostatin analogs (octreotide, lanreotide), GH receptor antagonist (pegvisomant).
  • Adjunctive medication may be considered for ACTH-secreting tumors or refractory cases.
  • Hormone replacement therapy for hormone deficiencies: Glucocorticoids (adrenal cortical hormones), thyroid hormone (levothyroxine), sex hormone therapy, etc.
• Surgery
  • Typical method: Endoscopic transsphenoidal surgery — preferred indication for large or compressive tumors (visual field defects or neurological symptoms).
  • If visual field defects are caused by the tumor, rapid decompression through surgery can restore vision in up to approximately 90% of cases.
  • Surgical complications: Cerebrospinal fluid leakage (CSF leak), diabetes insipidus, infection, optic nerve damage, etc.
• Radiation therapy
  • Indications: When surgery is not possible, when residual or recurrent tumor remains after surgery, or when repeated surgery would impose a burden.
  • Methods: Stereotactic radiosurgery (such as Gamma Knife) or external-beam radiation (fractionated radiation).
  • Long-term side effects: Hypopituitarism, optic nerve damage, and, rarely, radiation-induced secondary tumors.
• Lifestyle management and follow-up
  • Regular hormone tests and MRI (initially at 3–12-month intervals depending on the lesion and treatment, followed by long-term follow-up).
  • Bone mineral density assessment (for patients with long-term hyperprolactinemia or sex hormone deficiency).
  • Consultation with a specialist when planning pregnancy (for prolactinoma, medication discontinuation/continuation and monitoring during pregnancy need to be addressed).
• Precautions (patient self-management)
  • Patients requiring steroid replacement should not stop it on their own (the dose may need to be increased during stress).
  • Seek emergency medical care immediately in the event of acute worsening, such as headache, worsening vision, or vomiting (suspected pituitary apoplexy [thrombosis/hemorrhage]).
  • Regular medical examinations are necessary for medication side effects (e.g., dizziness and indigestion from dopamine agonists, and, rarely, heart valve problems).
  • Hormone deficiencies must be monitored after radiation therapy.

Checklist Before an Outpatient Visit (Items, Records, and Example Questions)

• Items/materials to bring
  • A list of all medications currently being taken (including prescription, over-the-counter, and herbal medicines)
  • Previous test results: Brain MRI (original images if possible), serum hormone test results, and visual field testing results (visual field test report)
  • Symptom diary: Frequency/intensity of headaches, onset and pattern of visual changes, menstrual changes (women), changes in sexual function, and the onset of galactorrhea
  • Possibility of pregnancy/breastfeeding status (women)
  • Underlying conditions (cardiovascular disease, diabetes, osteoporosis, etc.)
• Items useful to record at the outpatient visit
  • Onset of symptoms and pattern of progression
  • Recent weight changes, fatigue, and changes in urine volume (polyuria/polydipsia)
  • History of brain surgery or radiation therapy
• Simple example questions to check before the visit (for patients)
  • Is your vision blurry, or are you unable to see in your peripheral vision?
  • Are you producing breast milk (galactorrhea)? Are your periods regular?
  • Have you recently experienced changes in libido or reduced sexual function?
  • Are you pregnant or planning to become pregnant?

General Example Questions to Ask the Doctor

• "What type of pituitary tumor do I have (functional/nonfunctional, and which hormone does it secrete)?"
• "Among the treatment options (medication, surgery, and radiation), which should be prioritized, and why?"
• "What are the expected effects and major side effects of drug treatment?"
• "What is the recovery process after surgery, and how high is the risk of complications?"
• "What schedule should be followed for follow-up tests (hormone tests and MRI) after treatment?"

Tailored Example Questions by Disease

• (When a prolactin-secreting adenoma is suspected or confirmed) "I am planning a pregnancy. Is it safe to stop the medication (cabergoline)? What will the monitoring plan be during pregnancy?"
• (When visual field defects are present due to a macroadenoma) "To what extent is vision recovery expected after surgery? What will the schedule be for visual field tests before and after surgery?"

(Summary for Reference)

• Treatment for pituitary tumors varies according to symptoms, size, and hormone secretion. MRI and blood hormone tests are central to diagnosis. Prolactinomas are treated first with dopamine agonists (such as cabergoline), and endoscopic transsphenoidal surgery is considered first when there is a mass effect, such as visual field defects. Regular endocrine and imaging follow-up and a multidisciplinary approach are important.