Thyroglossal duct cyst

Disease Description (Causes and Symptoms)

• Definition summary: A condition in which the pituitary gland (an endocrine gland approximately 1 cm in diameter located just below the hypothalamus) secretes excessive hormones, causing systemic symptoms. In most cases, the cause is a pituitary tumor (adenoma).
• Main pathophysiology: Excessive secretion of specific pituitary hormones (e.g., prolactin, growth hormone, ACTH) from a tumor or hyperactive cells causes hyperfunction of target organs (the thyroid gland, adrenal glands, gonads, etc.) and systemic metabolic abnormalities. If the tumor is large, it may compress the optic nerves and cause visual field defects.
• Common causes: Pituitary adenoma (functional adenomas: prolactinoma, GH-secreting adenoma, ACTH-secreting adenoma, etc.), and rarely malignant tumors
• Main symptoms (examples according to hormone type):
  • Excess prolactin: Galactorrhea (not related to pregnancy or breastfeeding), amenorrhea, infertility, decreased libido (men)
  • Excess growth hormone: Gigantism during growth, acromegaly in adults (enlargement of the hands, feet, and face), joint pain, excessive sweating, carpal tunnel syndrome
  • Excess ACTH (Cushing disease): Round face, central obesity, thin arms and legs, hypertension, diabetes, osteoporosis
  • General symptoms: Fatigue, sweating, facial edema, hypertension, diabetes, visual disturbances (bitemporal hemianopia), headache

Treatment Methods

• General principles: Treatment is selected according to the type of hormone excessively secreted and the tumor's size and location. The goals are to normalize hormone levels, reduce tumor size, preserve the optic nerves, and prevent complications.
• Medication
  • Prolactinoma: Dopamine agonists (cabergoline as first-line treatment, bromocriptine as an alternative) — effective for suppressing hormone secretion and reducing tumor size.
  • Growth hormone-secreting adenoma (acromegaly): Somatostatin analogues (octreotide, lanreotide), GH receptor antagonist (pegvisomant), etc.
  • ACTH-secreting pituitary tumor (Cushing disease): Selective agents such as pasireotide may be used before surgery or as adjunctive therapy, or adrenal steroid synthesis inhibitors (ketoconazole, metyrapone, etc.; mainly in consultation with endocrinology/internal medicine).
• Surgery
  • Transsphenoidal (transsphenoidal) approach (reaching the pituitary gland through the nose) — standard first-line treatment, particularly depending on the tumor's size and extent of invasion.
  • Transcranial approach (craniotomy) — used for large or atypical lesions, or when a transsphenoidal approach is not possible.
• Radiation therapy
  • If complete removal by surgery is not possible, or in cases of recurrent or residual tumor, radiation therapy such as Gamma Knife or a linear accelerator, or Gammaknife, may be used.
• Postoperative and adjunctive treatment
  • Hormone replacement when necessary (e.g., cortisol, thyroid hormone, etc. for pituitary insufficiency after surgery).
• Lifestyle management and precautions
  • Control blood pressure and blood glucose, evaluate and manage osteoporosis, manage body weight, and monitor for infection and complications before and after surgery.
  • If pregnancy is planned, discuss medication and surgical plans with a specialist (particularly for prolactinoma).

Outpatient Visit Checklist (Including Items to Prepare and Example Questions)

• Items to prepare (before visiting the hospital)
  • List of medications currently being taken (prescriptions/medication bags) and recent dosages
  • Copies of previous test results (recent MRI/CT, blood tests, visual field test results, etc.)
  • Symptom record: onset, pattern of changes (menstrual abnormalities, galactorrhea, visual changes, headache, sweating/fatigue, etc.)
  • Lifestyle notes: changes in body weight and records of self-measured blood pressure and blood glucose, if available
  • Pregnancy plans or contraceptive status (for women)
• Key symptoms to tell the doctor about in advance during the outpatient visit
  • Blurred vision or partial loss of the visual field (particularly the peripheral visual field)
  • Abnormal galactorrhea, amenorrhea/decreased libido
  • Acute worsening (severe headache, sudden decrease in vision)
• Information that is useful to provide to medical staff before testing
  • History of previous brain surgery or head trauma, history of radiation therapy, and history of other endocrine diseases (thyroid disease, diabetes)

General Example Questions to Ask the Doctor

• "Which hormone is excessive in my case, and what are the confirmed blood test levels and their meaning?"
• "Among the treatment options (medication, surgery, and radiation), why do you recommend this option, and what effects can be expected?"
• "What recovery and risks can be expected with surgery (visual impairment, cerebrospinal fluid leakage, pituitary insufficiency, etc.)?"
• "How long does it usually take for hormone levels to return to normal after treatment? What is the schedule for follow-up tests?"
• "What are the side effects of treatment and the precautions I should take in daily life?"

Examples of Disease-Specific Questions

• Regarding prolactinoma:
  • "Is my prolactin level high enough to be clinically concerning? If I start medication (cabergoline), how should I adjust my pregnancy plans?"
• Regarding growth hormone-secreting adenoma (acromegaly):
  • "What is the target IGF-1 (insulin-like growth factor-1) level, and how should the OGTT (oral glucose tolerance test) results for GH suppression be interpreted?"
• Regarding ACTH secretion (Cushing disease):
  • "What do the results of the 24-hour urinary free cortisol test or dexamethasone suppression test mean, and how will steroid replacement be managed before and after surgery?"
• Regarding visual and neurological symptoms:
  • "What are the results of my current visual field test (perimetry), and to what extent is the optic nerve being compressed by the tumor?"

Follow-up Management Recommendations (Summary)

• After the diagnosis is confirmed, regular hormone testing (prolactin, IGF‑1, GH, ACTH/cortisol, etc.) and follow-up pituitary MRI are necessary (3–6 months after the initial surgery, followed by approximately once a year depending on the situation).
• Check for pituitary insufficiency after surgery and provide hormone replacement therapy when necessary.
• If visual abnormalities occur, seek immediate emergency evaluation (visual field testing and ophthalmology consultation are recommended).

(Note: The initiation or discontinuation of specific medications and the indication and timing of surgery vary according to each patient's condition. These decisions must be made in consultation with the attending endocrinology/internal medicine or neurosurgery specialist.)