Clinical aspects of histological and hormonal parameters in boys with cryptorchidism: Thesis for PhD degree

Undescended Testes Growth Potential in Relation to Testis Position from Diagnosis until Puberty

Background: Testicular volume (TV) and testicular atrophy index (TAI) were used to determine criteria for normal, hypotrophic and atrophic undescended testes (UDT). Objectives: This study aimed to determine changes in TV and TAI in patients with different types of UDT. Materials and Methods: 182 boys (aged 0.3-14.0 years) with 212 UDTs were assessed twice 24 months apart. Testes were unilateral (UCT) or bilateral canalicular (BCT) and intra-abdominal (IAT). Results: At the beginning of the observation, the highest TAI was observed in IAT and the lowest in the BCT group (38.1 vs. 12.5%, p < 0.05). After 2 years, the highest TAI was observed in the BCT and IAT groups (20.5 and 19.1%), while the lowest was in the UCT group (12.0%, p < 0.05). At the beginning and after 2 years, the highest TAI was observed in boys aged < 6 years (25.0%, 18.2%) and the lowest in pubertal boys aged 12-14 years (5.9%, 7.3%, p < 0.05). A total of 78.3% of patients at the beginning and 86.8% at the end of the observation had TAI < 30%. Furthermore, 7% of boys at the beginning and 3% at the end of the observation had TAI > 50%. IATs have the highest testicular growth potential (TGP), while BCTs have the lowest (120.0 vs. 28.6%, p < 0.05). The highest TGP was in boys aged < 3 years (100%, p < 0.05) and boys aged 12-14 years (98.1%, p < 0.05), while the lowest was in boys aged 9-10.9 years (19.5%, p < 0.05). Conclusions: We revealed the continuous growth of UDTs until puberty independently of their position. IATs revealed high growth potential.

Anogenital distance in a cohort of 169 infant boys with uni- or bilateral cryptorchidism including 18 boys with vanishing testes

STUDY QUESTION

Do different boys with different types of cryptorchidism exhibit different anogenital distances (AGDs)?

SUMMARY ANSWER

Length of AGD seemed to differ in different groups of patients with cryptorchidism.

WHAT IS KNOWN ALREADY

AGD, which is used as an indicator of prenatal androgen action, tends to be shorter in boys with cryptorchidism compared to unaffected boys. Shorter AGDs have also been reported in boys with hypospadias, in men with poor semen quality, and in men with testicular cancer.

STUDY DESIGN, SIZE, DURATION

A prospective descriptive cohort study was performed using data from consecutively selected boys with cryptorchidism (n = 169) operated in a single center over a period of 3 years (September 2019 to October 2022).

PARTICIPANTS/MATERIALS, SETTING, METHODS

AGD was measured in 169 infant boys, at 3 to 26 months of age, during anesthesia with a vernier caliper measuring the distance from the anus to the base of the scrotum (AGDAS) and from the anus to the anterior base of the penis (AGDAP) in two body positions according to the methods by 'The Infant Development and the Environment Study' (TIDES) and 'Cambridge Baby Growth Study', resulting in four mean values per patient (TIDES AGDAS/AP and Cambridge AGDAS/AP). Normal values for AGD by age were set by our hospital Department of Growth and Reproduction based on a large cohort of healthy infant boys (n = 1940). Testicular biopsies were performed at orchidopexy as a clinical routine. The germ cell number (G/T) and type Ad spermatogonia number (AdS/T) per cross-sectional tubule of at least 100 and 250 tubules, respectively were measured and related to normal samples. Blood samples were obtained by venipuncture for measuring serum LH, FSH, and inhibin B. They were analyzed in our hospital Department of Growth and Reproduction where the normal reference was also established. Correlations between the four mean AGD measurements for each boy were evaluated by Spearman rank correlation analyses. The AGD measurement of every boy was transferred to the multiple of the median (MoM) of the normal AGD for age and named MoM AGD.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 104 boysoperated for unilateral, and 47 boys operated for bilateral, undescended testes, whereas 18 boys had vanished testis including one boy with bilateral vanished testes. Only 6% of cases with vanished testes had a MoM AGD higher than the normal median compared to 32% with undescended testes (P < 0.05). MoM AGD increased with the age at surgery for boys with vanished testis (Spearman r = 0.44), but not for boys with undescended testes (Spearman r = 0.14). Boys with bilateral cryptorchidism had longer AGDs and more often had hypogonadotropic hypogonadism than boys with unilateral cryptorchidism (P < 0.005) and (P < 0.000001).

LIMITATIONS, REASONS FOR CAUTION

Although being the largest published material of AGD measurements of infant boys with cryptorchidism, one limitation of this study covers the quite small number of patients in the different groups, which may decrease the statistical power. Another limitation involves the sparse normal reference material on G/T and AdS/T. Finally, there are currently no longitudinal studies evaluating AGD from birth to adulthood and evaluating childhood AGD in relation to fertility outcome. Our study is hypothesis generating and therefore the interpretation of the results should be regarded as exploratory rather than reaching definite conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

The study findings are in agreement with literature as the total included group of boys with cryptorchidism exhibited shorter than normal AGDs. However, new insights were demonstrated. Boys with vanished testis had shorter AGDs compared to unaffected boys and to boys with undescended testes. This finding challenges the current concept of AGD being determined in 'the masculinization programming window' in Week 8 to 14 of gestation. Furthermore, boys with bilateral cryptorchidism had longer AGDs and more often had hypogonadotropic hypogonadism than boys with unilateral cryptorchidism, suggesting that the lack of fetal androgen in hypogonadotropic hypogonadism is not that significant.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used and no competing interests are declared.

TRIAL REGISTRATION NUMBER

The trial was not registered in an ICMJE-recognized trial registry.

The fate of germ cells in cryptorchid testis

Cryptorchidism in males constitutes a notable risk factor for both infertility and testicular cancer. Infertility in adulthood is closely linked to the germ cell status in childhood. Furthermore, the significance of germ cell status is important as more than 95% of all reported testicular malignancies are germ cell tumors. The review aims to elucidate the pathogenesis of germ cells in cryptorchid testes concerning their association with infertility and testicular malignancies. Impaired germ cell numbers are evident in cryptorchid testes even during antenatal and neonatal stages. In cryptorchidism there is a rapid decline in germ cell number within the first year of life, partially attributed to physiologic gonocyte apoptosis. Additionally, germ cells fail to differentiate normally during mini-puberty leading to reduced germ cell proliferation and delayed clearance of gonocytes from the seminiferous epithelium. Absence of germ cells in testicular biopsies occurs already 10 months of age and germ cell deterioration progressively worsens with approximately 50% of persisting cryptorchid testes lacking germ cells during puberty. The deficient germ cell maturation and proliferation leads to later infertility. Elevated temperature in the cryptorchid testes and also hormonal deficiency contribute to this phenomenon. Germ cell neoplasia in situ (GCNIS) originating during fetal development may manifest in rare cases associated with disorders of sexual development, chromosomal abnormalities in boys, specific syndromes, and teratomas that include cryptorchidism. In adults, the presence of GCNIS predominantly represents a new histology pattern before invasive germ cell cancer is demonstrated and is neither congenital nor related to abnormal gonocyte transformation.