Testicular hypoplasia is a congenital underdevelopment of one or both testicles, leading to androgen deficiency. Disease is accompanied by a decrease in the size and asymmetry of the scrotum, a small penis size, a violation of puberty, pseudohynecomastia, decreased libido, impotence, male infertility. The diagnosis is based on examination and palpation of the scrotum, the results of ultrasound of the scrotum organs, spermograms, studies of the level of total and free testosterone. Treatment includes hormone replacement therapy, prosthetics of an underdeveloped testicle, transplantation of a donor organ.
General information
Testicular hypoplasia is a malformation of the male sex glands associated with the small size and insufficient function of one or both testicles. Testicular malformations occur in 5-7% of newborn boys. Among the congenital disorders, anomalies of the number (anorhism, monorhism, polyorhism), position (cryptorchidism, ectopia) and structure (hypoplasia and aplasia) of the testicles are distinguished. Testicular hypoplasia can manifest itself to varying degrees: from a slight decrease in the size of the gonads to their complete absence. Testicular hypoplasia can be unilateral (underdevelopment of the left or right testicle, the second is normally developed) and bilateral (the size of the left and right testicles is significantly less than normal).
Testicles (testes, testicles) are paired male sex glands and perform a dual function: reproductive (production and maturation of male germ cells – sperm) and endocrine (incretion of the main male sex hormone – testosterone). It is the testicles that determine the development of primary and secondary sexual characteristics and the realization of reproductive potential in men. The testicles have a dense consistency, oval, slightly flattened shape. Their sizes are normally: 4-5 cm in length, 2-3 cm in width; weight 20-30g.
The testicles are located in the scrotum and are separated by a septum. This localization of the testicles is associated with the achievement of an optimal temperature regime (32 ° C) necessary for spermatogenesis. Each testicle is covered with several shells and consists of lobules filled with a network of straight and convoluted seminal tubules. The appendage of the testicle is closely attached to the posterior surface of each testicle, in which the vas deferens begins.
Causes
Testicular hypoplasia develops due to a violation of their formation in the early stages of the embryonic period. The earlier the damage occurs, the more pronounced the degree of anomaly. Normally, the sex glands begin to form from two germ structures: the wolf’s and Muller’s ducts in the indifferent stage of embryogenesis. In the future, gonad differentiation occurs in accordance with the genetic sex of the fetus. Testicular formation is regulated by the SRY gene on the short arm of the Y chromosome, encoding a special protein – the testicular development factor.
The testicles of the embryo become an active endocrine organ very early: under the action of testosterone synthesized by them, the appendage of the testicle, the vas deferens and the seminal vesicle are formed from the wolf ducts, and under the influence of the anti-Muller factor, the development of the muller ducts in the male fetus is suppressed. The laying of the testicles in the embryo occurs in the abdominal cavity, but by the time of birth they descend through the inguinal canal into the scrotum. Testicular development continues actively at puberty and ends by the age of 17-18.
The main cause of testicular hypoplasia is chromosomal and genetic abnormalities (violation of the number or structure of sex chromosomes, damage to the genes responsible for the differentiation of fetal sex). For example, testicular hypoplasia in Klinefelter syndrome is associated with the presence of extra X chromosomes in the karyotype (47XXX, 48XXXY); in Shereshevsky-Turner syndrome, with translocation of part of the X chromosome to the Y chromosome or X chromosome mosaicism. In rudimentary testicular syndrome, the formation of internal genitalia occurs simultaneously from the Muller and wolf ducts and leads to the formation of underdeveloped female and male genitalia in the child.
Predispose to the development of testicular hypoplasia may be pregnancy pathology, hormonal imbalance (taking estrogens and progestin drugs, the presence of hormone-active tumors), teratogenic effects of various factors on the intrauterine development of gonads, damage to the child’s central nervous system during severe childbirth. Hypoplasia of the testicles may be accompanied by hypoplasia of other endocrine organs, for example, the thyroid gland. Often, the cause of testicular hypoplasia may be trophic changes or autoimmune lesion of testicular tissue, leading to impaired gonadal development. The risk of testicular hypoplasia in boys increases if the disease is of a family nature.
Symptoms
Testicular hypoplasia is often asymptomatic and is detected accidentally when a patient visits a urologist about a infertile marriage. With hypoplasia of the testicles, the scrotum looks smaller than normal due to a decrease in the size of one or both glands, ranging from 0.5-0.7 to 2.5 cm. Hypoplasia of the appendages of the testicles and prostate is also characteristic.
The main sign of testicular hypoplasia is a violation of the hormonal background; at the same time, the severity of the pathology is determined by the degree of decrease in testosterone. With unilateral testicular hypoplasia, due to compensatory mechanisms, the second healthy gland takes over some of the functions, so the hormone level changes slightly. At the same time, a healthy testicle noticeably increases in size. With a small degree of testicular hypoplasia, spermatogenesis proceeds normally, and a man is able to conceive a child on his own.
In bilateral lesions, the main manifestations of testicular hypoplasia are acute androgen deficiency, impaired puberty, eunuchoidism, decreased libido, impotence, impaired spermatogenesis (oligoastenoteratozoospermia, asthenoteratozoospermia, teratozoospermia). Delayed puberty with testicular hypoplasia is characterized by underdevelopment of secondary sexual characteristics in boys older than 14 years: insufficient pubic and axillary hair, lack of coarsening of the voice, nocturnal emissions, infantile external genitalia (small penis less than 5 cm, testicular volume less than 4 ml, lack of folding and sagging scrotum). The physique of such patients is disproportionate, closer to the female type; pseudogynecomastia is characteristic.
Testicular hypoplasia occurs in alcoholic embryophetopathy, hypogonadism, adrenal tumors (corticosteroma), various syndromes (Kleinfelter, Alstrom-Olsen, Shereshevsky-Turner, Bard-Bidl, etc.), pituitary nanism, epispadias. Testicular hypoplasia can lead to serious consequences: male infertility, testicular atrophy and degeneration, the development of prostatitis, malignant tumors (testicular cancer).
Diagnostics
Diagnosis of testicular hypoplasia is carried out by an endocrinologist or andrologist based on the results of anamnesis, objective examination and palpatory examination of the scrotum area, assessment of the size and symmetry of the testicles, ultrasound of the scrotum organs. In most cases, this examination is informative enough to detect testicular hypoplasia. If testicular hypoplasia is combined with cryptorchidism, diagnostic laparoscopy is indicated.
In adult patients, a spermogram is additionally examined, the level of total and biologically active testosterone in the blood serum is determined. To identify possible chromosomal or genetic abnormalities in testicular hypoplasia, a karyotype study and genetic analysis are performed. Pronounced testicular hypoplasia must be differentiated from cryptorchidism, monarchism, testicular ectopia.
Treatment
Treatment of testicular hypoplasia in the vast majority of cases is medicamental, consists of hormone replacement and stimulation therapy (HRT). In case of unilateral lesion, regular monitoring of hormonal status is carried out, testosterone preparations are prescribed according to indications. When combined with testicular hypoplasia with teratozoospermia, therapy with chorionic gonadotropin is indicated. Hormonal stimulation of spermatogenesis makes it possible to improve the morphology of spermatozoa for a long time, to increase the effectiveness of ICSI and IVF, to be able to cryopreservate sperm and use it in the long term. With bilateral testicular hypoplasia, HRT helps to achieve the normal development of secondary sexual characteristics in adolescents.
With hypoplasia of one testicle and the normal functioning of the second, surgical removal of an underdeveloped organ (orchiectomy) is performed, and later, at the request of the patient, its aesthetic prosthetics (implantation of an artificial testicle). To achieve hormonal compensation, alloplastic transplantation of a donor testicle is possible. To eliminate the possible mental trauma of testicular hypoplasia, the help of a psychologist, a psychotherapist is needed.
Prognosis and prevention
After hormonal and surgical treatment of unilateral testicular hypoplasia, sexual life is improved in patients, it becomes possible to conceive a child. In the case of a pronounced bilateral lesion, absolute infertility is diagnosed.
Prevention of testicular hypoplasia consists in eliminating negative effects on the body of a pregnant woman, conducting medical and genetic counseling of married couples, according to indications – invasive prenatal diagnosis during pregnancy. For timely detection of testicular hypoplasia, timely preventive examinations of children and adolescents by specialist doctors are important: pediatrician, pediatric endocrinologist, pediatric surgeon, pediatric urologist.