Introduction. The problem of future fertility in boys with cryptorchism is studied for a long time and versatile. It is known that this malformation in 50-70% of cases is complicated by testicular tissue hypoplasia, which increases the risk of loss or reduction of reproductive function. But the severity of hypoplasia of the undescended testicle has not been studied enough. The purpose of the study is to study the histological and ultrastructural characteristics of testicular hypoplasia in cryptorchidism in children.

Materials and methods. Morphological(light-optical microscopy) and electron-microscopicstudies of 36 biopsy specimens of the tissue of the neoplastic testis with unilateral cryptorchidism (inguinal retention or ectopia) were performed in accordance with the modern research data algorithm using the following equipment: microtomy was performed on a HM-450 MICROM microtome; the morphology and morphometry of the preparations was performed on a Olympus CX41 microscopewith magnification x50, x100, x200, x400; ultrathin sectionswere obtained on a Leica EM UC6 ultratome and examined using a Morgagni 268 electron microscope. To assess the degree of hypoplasia of the testicular tissue, morphometric indicators were selected thatcharacterize the condition of the seminiferous tubules: average diameter of the seminiferous tubules, number of layers of germinogenic epithelium, number of Sertoli cells per tubule and tubular index fertility. Statistical analysis was performed based on the Gretl software package (Gnu Regression, Econometrics and Time-series Library, 2014).

Results and discussion. A correlation was established between light-optical and electron-microscopic pathological changes in the tissue of the gonad that did not descend into the scrotum in accordancewith the severity of hypoplasia: dystrophic and fibroplasticchangesin the germinal tubule epithelium increase at the ultrastructural level.

Conclusions. Adetailed description of pathomorphological, morphometric, and ultrastructuralchangesin the hypoplastictestisindicatesthat in 83.3% of boys with cryptorchidism, structural disorders are the basis for a decrease in functional potential.

Conflict of interest. The authors declare no conflict of interest.