The essence in brief:
Pituitary adenomas are benign tumors that develop in the pituitary gland, specifically in the anterior pituitary lobe. They can either produce hormones or be hormonally inactive. The most common types are prolactinomas, growth hormone-secreting adenomas, and ACTH-producing adenomas.
Symptoms and diagnoses vary depending on the type of adenoma. Acromegaly, Cushing’s disease, and prolactinomas have distinct clinical presentations. Diagnosis typically involves hormonal analysis and imaging techniques such as MRI.
Other tumors can also occur in the sella region, including craniopharyngiomas, meningiomas, germinomas, and gliomas. Metastases from breast, prostate, and renal cell carcinomas, as well as lymphomas and granulomatous diseases, can also affect the pituitary gland.
Pituitary adenomas and other space-occupying lesions can cause hormonal deficiencies, resulting in various symptoms. These deficiencies may include ACTH, TSH, LH/FSH, growth hormone, or ADH deficiencies. Additionally, the size of the tumor can lead to headaches and visual field defects if it compresses the optic chiasm.
Treatment approaches depend on the specific type and size of the adenoma. Options may include medication, surgery, radiation therapy, or a combination of these methods. Regular monitoring is important to assess hormone levels and tumor growth.
Overall, pituitary adenomas require proper diagnosis, treatment, and management to address hormonal imbalances and minimize potential complications.
Pituitary adenomas are benign tumors of the anterior pituitary gland. Pituitary adenomas can either produce hormones or be hormonally inactive (approximately 40% of pituitary adenomas are hormonally inactive). The most common type (30%) is prolactinoma, followed by growth hormone-secreting adenoma (20%), and less commonly, ACTH-producing adenoma (5%). Pituitary adenomas that produce TSH or LH/FSH are very rare. Pituitary carcinomas are rare and can also be hormonally active.
Acromegaly, Cushing’s disease, and prolactinomas have distinct clinical presentations, and therefore, the diagnostics are performed as described in each individual chapter.
In addition, other space-occupying processes can be found in the pituitary gland. The most common are hormonally inactive pituitary adenomas. Autopsy studies have found microadenomas of the pituitary gland in up to 27% of cases. Pituitary adenomas have been discovered in 10-20% of skull MRI examinations. These incidentally discovered pituitary adenomas (incidentalomas) require basic diagnostics. If there are clinical signs of hormone overproduction, such as in Cushing’s syndrome or acromegaly, an endocrinologist should conduct further investigations. If no clinical signs are present and the adenoma is smaller than 1 cm, determining the basal hormone levels is sufficient. If these levels are normal, a follow-up MRI examination in one year is appropriate. In the case of a macroadenoma (>10 mm), pituitary insufficiency must be ruled out. If there are clinical symptoms such as visual field defects and headaches, surgery is usually required. In cases of sudden severe headaches, the cause may be “stroke” of the pituitary adenoma (tumor apoplexy). The risk of rapid space-occupying growth with pressure on the optic nerve crossing exists due to hemorrhage, which can lead to blindness. In such cases, immediate hospital admission is necessary.
In the sella, tumors from other tissues can also be found, such as the hypothalamic-pituitary stalk. These include craniopharyngiomas, meningiomas, germinomas, and gliomas. Metastases from breast and prostate carcinomas can also be found in the pituitary gland, as well as, less commonly, metastases from renal cell carcinomas. Lymphomas and granulomatous diseases such as sarcomas, etc., can also occur in the pituitary gland. Cysts of Rathke’s pouch and epidermoid cysts are relatively common as well.
All these space-occupying lesions, including hormonally active pituitary adenomas, can cause a loss of pituitary functions.
ACTH deficiency: Patients complain of lack of drive, weakness, and fatigue. In advanced stages, weight loss, nausea, and vomiting can occur. Frequent episodes of hypoglycemia can also occur with ACTH deficiency.
TSH deficiency manifests as hypothyroidism (see Hypothyroidism chapter).
LH/FSH deficiency in women leads to menstrual cycle disorders, amenorrhea, and loss of libido. Men may complain of loss of libido and potency and may be infertile.
Growth hormone deficiency can also lead to reduced performance in adults. Patients often have central obesity and lipid metabolism disorders. Growth hormone deficiency also leads to bone loss (osteoporosis).
If the posterior pituitary is affected, there is ADH deficiency. Patients have diabetes insipidus, which, if untreated, leads to high fluid intake of 5-20 liters with corresponding urine output.
In addition to the symptoms caused by hormone deficiencies, the space-occupying lesion can cause symptoms due to its size. Headaches are often reported by patients. If the optic chiasm (crossing of optic nerves) is compressed by the lesion, there is a restriction of the visual field. The upper lateral quadrants of the visual field are affected.