Gynecomastia means benign growth of mammary glands in men. In addition to the fact that it is often an aesthetic problem, in 50% of cases gynecomastia is a sign of some disease or a consequence of taking a certain medication. First of all, it should be distinguished from the so-called pseudogynecomastia (adipomastia), in which there is fat accumulation in the upper part of the anterior chest wall and no glandular tissue around the areola of the breast is palpable. Once it is established that it is true gynecomastia, which is done by palpation of a palpable seal under the areola of the breast to the size typical of young women, its etiology should be specified. The reasons can be many. Three physiological forms of gynecomastia are known: neonatal, pubertal and involutive. The mechanisms by which they develop are presented in Gynecomastia – male breast enlargement. The most common endocrine diseases occurring with gynecomastia are: Klinefelter’s syndrome, in which there is a chromosomal aberration (karyotype 47 XXY); orchitis, trauma to the testicles and other diseases occurring with a violation of testosterone synthesis; androgen resistance syndrome; hyperthyroidism. Testicular tumors secreting estrogens or human chorionic gonadotropin also occur with the development of gynecomastia. Human chorionic gonadotropin can also be secreted by tumors of the lung or digestive system. In liver cirrhosis, a reduced catabolism of androstenedione is observed, which is converted into estrogen in the peripheral tissues. The serum concentration of sex-hormone binding globulin, which binds testosterone with high affinity and reduces its biologically active concentration, is also increased. There is a general disturbance of the balance between androgens and estrogens. For the diagnosis of these diseases, it is appropriate to examine the serum levels of testosterone, estradiol, FSH (follicle-stimulating hormone), LH (luteinizing hormone), SCHG (sex-hormone binding globulin), beta-CHG (human chorionic gonadotropin) and alpha-fetoprotein. liver enzymes, creatinine, urea and uric acid. In young men, Klinefelter’s syndrome must first be ruled out, which, in addition to gynecomastia, presents with bilaterally small and firm testicles, while in testicular tumors only one testicle is enlarged. It should always be remembered that gynecomastia can be an early symptom of very serious diseases. To clarify its cause, drug and/or narcotic (abuse) use must first be ruled out, then a tumor of the testicles, adrenal glands, or other organ should be looked for. Breast cancer in men is usually unilateral, with great firmness and is fixed to the surrounding tissue. It should be considered when there is breast pull with crusts on it, wrinkling of the skin and palpable enlarged lymph nodes in the armpits. After excluding the many reasons for the occurrence of gynecomastia, it can be assumed that it concerns the so-calledidiopathic form – there is no reason for its appearance. NEWS_MORE_BOX The treatment of gynecomastia requires, first of all, the removal of the nox that caused it (a drug or another substance) and the treatment of the accompanying disease, the symptom of which is gynecomastia. A reverse development could be expected in a condition where the process of fibrosis and hyalinization of the affected tissues has not progressed significantly. Gynecomastia that has lasted more than a year is unlikely to go away on its own or with medication. In such cases, surgical treatment is most effective. Medical treatment can be tried for gynecomastia in the initial stage of development with anti-estrogens – Tamoxifen for 3 months of treatment or with local application of dihydrotestosterone. Gynecomastia is not a necessary prerequisite for the development of breast carcinoma, however, men with established enlargement of the mammary glands should remain under observation.