The surgical findings we presented in this paper provide additional information to our previously reported case series and enlightens the possible mechanisms related to this condition [
2]. The occurrence of TED was very high in this group of boys (5 occurrences—55.6%), and was complete in 4 cases. The expected frequency of this anomaly is only 0.9% in normal children and up to 8% in patients with cryptorchidism [
8]. In our series, none of the boys presented with abnormalities of the peritoneum-vaginal canal. Our children are comparable to those of cerebral palsy in relation to brain damage and high frequency of undescended testicles (36.4% in our children and 24% in children with cerebral palsy), however differ in relation to the frequency of inguinal hernias (none in our case series versus 56% in cerebral palsy) [
2,
9].
Our understanding of the pathogenesis of cryptorchidism in children with ZRM is developing, and this case series provides findings that can help to better understand this physiopathologic process. Although the mechanisms of testicular descent are multi-factorial, given the high prevalence of TED and absence of anomalies of the peritoneum-vaginal conduit, it is plausible to suggest that congenital ZIKV infections should be considered as a possible explanation for the interferences on the formation mechanisms of the testis and epididymis during embryogenesis. Transmission of the Zika virus through the seminal fluid has been identified [
10], which leads us to assume that there is a possible tropism of the virus to the gonadal and adnexal tissue. This possibility needs to be explored further in cadaver parts or testes submitted to orchiectomy. The frequency of gonadal appendix in our series (44.5% in the testes and 22.2% in the epididymes) was lower than the reported by Zdizvic [
11], who described a frequency of 78.7% in gonads located close to the external inguinal ring in 89 normal boys. All operated testes of our series were palpable close to the external inguinal ring. Testicular appendixes are remnants of the paramesonephric ducts, but their role in testicular descent has not been well established. The function of the gubernaculum, on the other hand, is to guide the descent of the testicles in the second phase (inguinoscrotal), through the action of testosterone and the genitofemoral nerve associated with abdominal pressure, and has been well documented [
12]. The finding of 100% ectopic gubernacular insertion in the pubic position could point this as being a possible mechanism responsible for the complete non-descent of these gonads and could also explain a lower, extra-abdominal location. The prevalence of ectopic gubernacular insertion in congenital cryptorchidism reported in the literature is low. Favorito [
13] found no gubernacular ectopic insertion in 101 patients with cryptorchidism with a mean age of 6.4 years. Meji-de Vries [
14], describing surgical findings in congenital cryptorchidism in 76 testes, found 17% of gubernacular insertion in the bottom of the scrotum and 57% in the upper scrotum, totalling 74% scrotal gubernacular insertion. Due to their location, the non-descending gonads in the children with ZRM would be subjected to thermal stress, which could contribute to a progressive loss of testicular mass and volume. In this series, children operated at three years presented with abnormally low testicular volume, and the reduction in volume was even greater in children operated at four years. Delayed surgery (i.e., beyond the recommended maximum of 18 months of age) [
5] may explain the lower testicular volume in the children with ZRM.