Pituitary adenoma (PA)

A pituitary adenoma is a benign neoplasm that is formed from the cells of the adenohypophysis (the anterior pituitary gland), which plays a huge role in maintaining the normal hormonal balance of the body. Adenomas located in the base of the skull (“Turkish saddle”), account for 10% of the number of all primary tumors that develop in brain tissues. Statistics show that almost every third adult has some pathology of the pituitary gland.
The danger of anterior pituitary adenoma
Most adenomas are tumors that, although they do not have morphological signs of malignancy, can adhere to and mechanically squeeze brain structures adjacent to the pituitary gland, which manifests itself in the form of visual, neurological and endocrine disorders. In addition, pituitary adenoma may be accompanied by such complications as apoplexy (hemorrhage into the tumor) and cystic degeneration.
Provocative factors
The causes of pituitary adenoma have not been fully determined. Currently, there are two main theories of the possible occurrence and growth of a tumor:
• Disturbed hypothalamic regulation of hormonal release,
• Theory of the internal “defect” of the pituitary gland.
According to the first theory, if there is insufficient production of peripheral endocrine gland hormones, excessive production of hypothalamic liberins or statin deficiencies, hyperplasia of the corresponding pituitary cells can occur with the subsequent development of pituitary adenoma.
The second theory sees the cause in gene disorders of a single cell of the pituitary gland, which lead to tumor transformation.
Modern approaches to the classification of pituitary tumors
The complicacy of the classification of pituitary adenomas lies in the fact that the pituitary gland anatomically refers to the nervous system, and functionally – to the endocrine system.
Classification can be carried out according to the following parameters:
1. By hormonal activity:
Hormone-active adenomas (plurihormonal adenomas can secrete several hormones, for example, prolacto-somatotropic hormone). The following are the most common types:
• prolactinoma
• somatotropinoma;
• corticotropinoma;
• thyrotropinoma;
• gonadotropinoma.
Hormonally inactive adenomas are classified based on their morphological features:
• ‘silent’ somatotrophic, corticotrophic (type I, II), gonadotrophic, thyrotrophic, lactotrophic adenomas;
• null cell adenomas;
• oncocytomas.
2. By size:
• picoadenoma: any side of the tumor does not exceed 3 mm;
• microadenoma: dimensions do not exceed 10 mm;
• macroadenoma: more than 10 mm in diameter;
• giant adenomas: from 40-50 mm and more.
3. By the nature of growth and location relative to the Turkish saddle:
• endosellar growth (inside the Turkish saddle);
• suprasellar (upward growth);
• infrasellar (downward growth);
• laterosellar (grows sideways into the cavity of the cavernous sinus, infratemporal fossa, etc.);
• antesellar (grows forward into the trellised labyrinth, orbit);
• retrosellar (grows back under the dura mater of the clivus, etc.).
If the correct diagnosis is not established at the stage of clinical manifestations of excessive secretion of pituitary hormones, and the neoplasm continues to grow, ophthalmic and neurological symptoms occur, which manifestation may vary depending on the direction of tumor growth.
Pituitary adenoma and pregnancy
In the case of prolactin-secreting pituitary adenomas lacking adequate treatment, these concepts are quite often incompatible. Due to the fact that the tumor secretes excessive prolactin, a woman cannot get pregnant. There are cases of the onset of this tumor already during pregnancy.
Other types of pituitary adenomas where the concentration of prolactin in the blood remains within the normal range do not interfere with the conception.
Pituitary adenoma treatment in a pregnant woman
After being diagnosed with this disease, a woman should be followed up by a gynecologist, an endocrinologist and a neurosurgeon throughout the entire period of pregnancy.
Symptoms, clinical signs and diagnosis of pituitary adenomas
To establish the diagnosis, a modern clinical practice uses the following levels of verification:
• Clinical and biochemical signs: characteristic signs of hormone-active pituitary adenomas: gigantism in children, acromegaly in adults, Cushing disease, etc. Hormone-inactive pituitary adenomas are found too.
• Neuroimaging and operating findings, including: dimensions, localization, invasion into surrounding structures, growth pattern, etc. These characteristics are crucial in the choice of therapeutic approach and prognosis.
• Microscopic examination of a biopsic tumor specimen. This gives the opportunity for a differential diagnosis between pituitary adenoma and other non-pituitary tumors (hypophysitis, pituitary hyperplasia, etc.)
• Immunohistochemical tumor examination.
• Electron microscopy.
• Molecular biology and genetic research findings.
To diagnose anterior pituitary tumors, informative is the identification of a group of characteristic symptoms, the so-called Hirsch triad:
• Endocrine disorders,
• Ophthalmic disorders,
• Radiographic changes in the Turkish saddle.
You can receive a detailed examination plan with a list of necessary tests to confirm or refute the diagnosis of “pituitary adenoma” by making an appointment for a preliminary consultation with a neurosurgeon.
Can a pituitary adenoma be treated?
Modern medicine offers new opportunities for successful control of this disease. Currently, the following methods are used in the treatment of pituitary neoplasms:
• drug treatment,
• surgical removal of a pituitary adenoma,
• radiotherapy.
Surgery for pituitary adenomas
Modern methods of surgical treatment of pituitary adenomas, depending on the direction of tumor growth, are:
• endoscopic transnasal removal of pituitary adenoma (transnasal surgery);
• various transcranial interventions in case of pronounced extrasselar tumor growth.
Combinations of the above are possible too.
Consequences and possible complications after removal of a pituitary adenoma
• injury to healthy pituitary tissue,
• visual impairment;
• cerebrovascular disturbance,
• liquorrhea,
• infection.
The endoscopic method minimizes the negative post-operative effects.
The period of stay in the hospital after the endoscopic removal of the pituitary adenoma is relatively short: if there were no complications during the operation, the periods may vary from 1 to 3 days.
After discharge, each patient, after the removal of pituitary adenoma, gets an individual rehabilitation program to avoid relapses.
Cost of the pituitary adenoma removal
The cost is calculated individually, for example, the price of the transnasal removal of pituitary adenoma will mainly depend on the consumables chosen by the patient (the company and the country of origin).
Prognosis
Complete recovery of lost visual function after surgical treatment of pituitary adenoma is possible only in the early stages of the development of visual disorders.
In case of impossible vocational rehabilitation due to irreversible visual defects or endocrine-metabolic dysfunction, the patients with pituitary adenoma are recognized permanently disabled.