Prolactinoma is a neoplasm of the anterior lobe of the pituitary gland, which has all the signs of good quality and actively secreting prolactin. When prolactinoma occurs in the male and female, significant distinctive features of the clinical symptomatology are noted, in connection with which the oncologists advocate the principle of selecting an individual treatment regimen for each patient.
Unfortunately, it is extremely rare for the patient to achieve full recovery with the existing prolactinoma, however, the introduction of new surgical techniques of therapy makes it possible to significantly improve the prognosis for this disease.
Prolactinoma of the pituitary gland
Prolactinum should be classified as benign tumors with localization in the pituitary gland, which accounts for at least a third of all episodes of pituitary oncopathology. The risk group for this form of the adenoma of the pituitary gland is women who are in reproductive age, where the size of the lesions does not exceed several millimeters. Among the male half of humanity, prolactinoma is considered an exception to the rule, however, in this group of patients the course of the disease is more aggressive with progressive infiltrative tumor growth and a tendency to malignancy.
A feature of prolactinoma, as a hormone-producing tumor, is its ability to synthesize prolactin in a high concentration in situations when it should not normally be in serum. For the normal functioning of the organs of the reproductive system, both women and men, the minimum synthesis of prolactin, which stimulates sexual function, is an indispensable condition. Stimulation of fertility in women is to regulate the normal cycle of menstruation and the regular onset of an effective period of ovulation. Under the influence of prolactin in the circulating blood in the male body, conditions are created for the normal production of testosterone and the preservation of the activity of spermatozoa.
The causes of prolactinoma
Despite carrying out a huge amount of research in the field of diagnosis of frequently occurring and rare oncopathologies of different localization, until now researchers have not been able to establish a reliable etiopathogenetic cause of prolactinoma.
It is believed that some hereditary diseases of a genetic nature, and in particular a multiple endocrine neoplasia of the first type, can become a background disease for the development of prolactinoma symptoms. Based on this pathogenetic theory, it can be assumed that there is a genetic predisposition to the development of prolactinoma in the category of patients suffering from endocrine neoplasia. This pathology is accompanied not only by hyperproduction of prolactin, but also by excessive synthesis of hormonal substances by the pancreas and parathyroid gland.
Despite the suggested assumptions about the genetic nature of prolactinoma, reliable detection of the gene in 100% of cases provoking the symptoms of prolactinoma failed to be realized.
Symptoms of prolactinoma
Depending on the parameters of the neoplasm and its location with respect to the pituitary fossa, two main groups of prolactin are distinguished: intrasseolar microprolactinone (the volume of the volumetric formation does not exceed 10 mm and the tumor does not exceed the bone boundaries of the Turkish saddle) and extrasemelic macroprolactinoma (increased tumor parameters exceeding 10 mm contribute to its spread beyond the bone boundaries of the Turkish saddle). Determining the parameters of the tumor and its location is important in determining the tactics of conducting and treating the patient.
The degree of intensity of certain clinical symptoms in the presence of the prolactinoma of the pituitary gland directly depends on the level of increase in prolactin production and its concentration in the blood, as well as on the degree of compression of the brain structures by the tumor substrate.
Macropropactinomas, which significantly increase the size of the pituitary gland, have a compressive effect on the optic nerves, therefore, in the presence of this prolactinoma of this type, the patient exhibits pronounced visual disturbances in the form of a narrowing of the field of view, duality of objects when viewed from close range. In a situation where the volume of the tumor substrate has a compression effect on the visual cross-section, the patient may experience a complete bilateral loss of visual function.
Neurological disorders can significantly worsen the patient's condition, and for prolactinoma these disorders are typical and occur in 70-80% of cases. Patients with large prolactinoma size complain of a constant headache of constrictive nature, depression of mood, combined with a painful sense of anxiety, a tendency to emotional lability and increased irritability. In a situation where the prolactinoma reaches a large size, it is able to exert an inhibitory effect on the production of pituitary hormones, which are secreted by this gland under normal conditions.
Despite the commonality of some clinical manifestations of prolactinoma observed in almost all patients in whom the tumor has reached large sizes, there are individual features of the clinical symptom complex in each specific case.
Thus, the debut of the clinical picture with the existing prolactinoma in women, manifests itself in the form of gradual progressive changes in the regularity of the cycle of menstruation from oligomenorrhea to the complete absence of menstrual discharge for a long period of time. In addition, that menstruation is irregular, they differ anovulatory, that is, a complete absence of the period of ovulation and the impossibility of conception of the child, which is a consequence of inadequate production of other pituitary hormones.
In some cases, women may have a so-called galactorrhea, that is, a small amount of breast milk that has nothing to do with normal lactation in the postpartum period. This symptom is not threatening with regard to provocation of breast diseases, however, its appearance is considered one of the signs of prolactinoma.
In connection with the fact that prolactin has a regulating effect on the process of the exchange of minerals, in particular calcium, involved in the process of organizing the structure of bone tissue, an increased concentration of this hormone in the blood provokes the development of osteoporotic changes in the bones of various localizations. Expressed osteoporosis promotes the appearance of pathological bone fractures of various anatomical regions. In addition, estrogen deficiency, resulting from hyperprolactinaemia , contributes to fluid retention in the female body, thereby provoking progressive weight gain.
In severe cases of prolactinoma, combined with hyperandrogenism, a woman can have increased hair embolism of the skin and acne.
In a situation where a woman is diagnosed with prolactinoma during pregnancy, great attention must be paid to diagnosing the signs of disease progression, since in this period the majority of patients have a significant increase in tumor parameters and the appearance of severe complications caused by compression of the brain structures. The presence of signs of disease progression is an absolute indication for abortion at any time.
Prolactinoma in men is accompanied by symptoms caused by a progressive decrease in testosterone production and subsequent disturbances in the process of physiological spermatogenesis. This pathology is manifested in a decrease in libido, the lack of erectile function and even the development of secondary infertility. Galactorrhea in the male category of patients is extremely rare, but in some patients the increased level of prolactin in the blood can provoke the development of gynecomastia of a one-sided or bilateral nature, as well as testicular hypotrophy. Patients suffering from prolactinoma with prolactin hyperproduction suffer from various pathologies of bone tissue associated with reduced bone mineralization.
Treatment of prolactinoma
The timely treatment is the key to success, since the consequences of prolactinoma, which has a malignant recurrent course, are very severe. In the situation when prolactinoma is represented by small tumor substrate size, not accompanied by significant changes in the patient's health status, specific treatment is not required and it can be limited to dynamic dispensary observation of the patient with an obligatory assessment of laboratory-instrumental dynamics of the tumor process.
When the tumor is small, but accompanied by disorders of the genital area and the impossibility of conceiving the child, the doctor must assess the need for restoring the reproductive function individually in each specific case. Macropropolactinomas are necessarily subject to medical and surgical correction, since their presence provokes severe complications.
The drugs of choice in the treatment of prolactin, accompanied by hyperproduction of prolactin, are the drugs of the group of dopamine antagonists. The use of drugs of this pharmacological group in 90% of cases contribute to complete restoration of fertility in women who are in the pre-menopausal period.
The only drug with proven efficacy for leveling the manifestations of prolactinoma is Bromocriptine in an average daily dosage of 2.5 mg orally. Due to the fact that this drug can provoke a number of adverse reactions on the part of the digestive organs, in order to minimize these manifestations, the intake of this drug should be combined with antagonists of the proton pump (Omez 1 dragee 2 times per day). Despite the pronounced effectiveness with respect to the normalization of the synthesis of prolactin, Bromkriptin is not characterized by prolonged action, so when the drug is canceled, a relapse of hyperprolactinemia may occur.
The method of surgical treatment of tumors of the pituitary gland, and in particular of suprassellar macroprolactinoma, is transsphenoidal resection, after which in 90% of cases a pronounced positive effect is observed during the first day in the form of normalization of prolactin concentration in the blood. The field of application of this type of treatment is the presence of prolactinoma in a woman of reproductive age, who is noted for individual intolerance of preparations of the group of dopamine antagonists.
In a situation where tumor resection is not accompanied by a persistent effect in the form of normalization of hyperprolactinemia and the patient retains clinical manifestations of the disease, it is advisable to supplement the treatment of prolactinoma with a long course of taking Bromkriptin in a maintenance dosage of 1.25 mg or radiotherapy. Of course, radiotherapy is not accompanied by rapid normalization of prolactin levels, however, a progressive decrease in its concentration has a more stable result. Radiotherapy as a monotherapy is not recommended, since this method of treatment increases the risk of hypopituitarism.
When appointing a method of treating prolactinoma, the primary responsibility of the attending physician is to explain to the patient the advisability of prolonged treatment, which gives a strong stable positive result and in 30% of cases leads to complete recovery of the patient. Elimination of only clinical manifestations is not an excuse for cessation of treatment, since in this pathology a recurrent course can occur.