Pituitary tumors

Pituitary tumors are a group of benign, less commonly malignant neoplasms of the anterior lobe (adenohypophysis) or posterior lobe (neurohypophysis) of the gland. According to statistics, pituitary tumors account for about 15% of intracranial neoplasms. They are diagnosed equally often in both sexes, usually at the age of 30-40 years.

Pituitary tumors are classified based on their size, anatomical location, endocrine functions, microscopic staining characteristics, etc. Depending on the size of the neoplasm, microadenomas (less than 10 mm in maximum diameter) and macroadenomas (with a maximum diameter of more than 10 mm) of the pituitary gland are distinguished. According to localization in the gland, tumors of the adenohypophysis and neurohypophysis are distinguished. Pituitary tumors, based on their topography relative to the sella turcica and surrounding structures, are endosellar (extending beyond the sella turcica) and intrasellar (located within the sella turcica). Based on their histological structure, pituitary tumors are divided into malignant and benign neoplasms (adenohypophysis). Adenomas originate from the glandular tissue of the anterior pituitary gland (adenohypophysis). Based on their functional activity, pituitary tumors are divided into hormonally inactive ("silent", incidentalomas) and hormonally active adenomas (producing a particular hormone), which occur in 75% of cases.

Symptoms

In 20% of patients, pituitary tumors are asymptomatic and are detected only during autopsy. Clinical manifestations of pituitary tumors depend on the hypersecretion of a particular hormone, the size and growth rate of the adenoma. As the pituitary tumor grows, symptoms from the endocrine and nervous systems develop. An increase in the size of the pituitary tumor leads to the development of manifestations from the nervous system. Since the pituitary gland is anatomically adjacent to the optic chiasm, then with an increase in the size of the adenoma to 2 cm in diameter, visual disturbances develop: narrowing of the visual fields, swelling of the optic nerve papillae and its atrophy, leading to a decrease in vision, up to blindness. Large pituitary adenomas cause compression of the cranial nerves, accompanied by symptoms of damage to the nervous system: headaches; double vision, ptosis, nystagmus, limited movement of the eyeballs; seizures; persistent runny nose; dementia and personality changes; increased intracranial pressure; hemorrhages in the pituitary gland with the development of acute cardiovascular failure. If the hypothalamus is involved in the process, episodes of impaired consciousness may be observed. Malignant pituitary tumors are extremely rare.

Risk factors

The exact causes of pituitary tumor development have not been fully studied, although it is known that some types of neoplasms may be genetically determined. Factors predisposing to the development of pituitary tumors include neuroinfections, chronic sinusitis, traumatic brain injury, hormonal changes (including those due to long-term use of hormonal drugs), and adverse effects on the fetus during pregnancy.