Differences in the morphology of the processus vaginalis with sex and underlying disease condition

A comparative study of smooth muscle cell characteristics and myofibroblasts in processus vaginalis of pediatric inguinal hernia, hydrocele and undescended testis

BACKGROUND

Congenital inguinal hernia, hydrocele and undescended testis (UDT) are associated with patent processus vaginalis. The smooth muscles present in the processus vaginalis aid in the descent of the testis and undergo programmed cell death after testicular descent leading to obliteration. The persisting amount of smooth muscle in the processus vaginalis influences the clinical outcome as inguinal hernia, hydrocele or UDT. Therefore, a study was conducted to evaluate the processus vaginalis in these three conditions to observe the presence and phenotype of smooth muscle cells and the presence of myofibroblasts.

MATERIALS AND METHODS

The processus vaginalis sacs in patients with inguinal hernia, hydrocele and UDT were examined using light microscopy for the presence and distribution of smooth muscle cells and immunohistochemical staining for vimentin, desmin, and α-smooth muscle actin (SMA) to identify the smooth muscle phenotype. Transmission electron microscopy was also performed in all the sacs to observe the presence of myofibroblasts.

RESULTS

Seventy-eight specimens of processus vaginalis (from seventy-four patients), distributed as 47%, 27%, and 26% as inguinal hernia, hydrocele and UDT respectively, were included in the study. The sacs from inguinal hernia and hydrocele had significantly more presence of smooth muscles distributed as multiple smooth muscle bundles (p < 0.001). Desmin and SMA staining of smooth muscle cells was observed in significantly more sacs from hydrocele, followed by inguinal hernia and UDT (p < 0.001). The sacs from UDT had a significant presence of striated muscles (p = 0.028). The sacs from inguinal hernia had a significant presence of myofibroblasts, followed by hydrocele and UDT (p < 0.001) and this significantly correlated with the light microscopy and immunohistochemical features. The processus vaginalis sacs from four female patients did not differ statistically from the male inguinal hernia sacs in any of the above parameters.

CONCLUSION

The processus vaginalis sacs in pediatric inguinal hernia, hydrocele and undescended testis differ in the presence, distribution and phenotype of smooth muscles and the presence of myofibroblasts. The clinical presentations in these entities reflect these differences.

Comparison of the Detection and Ligation of Patent Processus Vaginalis Between Laparoscopy-Assisted Transscrotal Orchiopexy and Single Scrotal Incision Orchiopexy

This study aimed to compare the detection and ligation of patent processus vaginalis (PPV) between laparoscopy-assisted transscrotal orchidopexy (LATO) and single scrotal incision orchiopexy (SSIO) for low palpable undescended testis (UDT). We performed a retrospective medical record review of transscrotal orchidopexies performed for low palpable UDT at our institution from 2017 to 2019; 33 and 39 boys underwent LATO and SSIO, respectively. Data collection included patient demographics, incidence of PPV, operative time, and clinical outcomes. All 95 testes were delivered into the scrotum. There was no significant difference between the two groups with respect to patients' age, side, and mean operative time. The incidence of PPV in the LATO group was significantly higher than that in the SSIO group (56.52 vs. 34.69%, P = 0.04). The incidence of contralateral PPV in the LATO group was 45%. One patient in the SSIO group underwent unilateral PV ligation and laparoscopic exploration revealed bilateral PPV owing to metachronous contralateral hydrocele. One patient in the LATO group demonstrated obliterated PV in the initial transscrotal procedure, but an ipsilateral PPV was found in the latter laparoscopic procedure. In conclusion, LATO has a higher detection rate and higher ligation of the PPV than SSIO, suggesting that, LATO may help reduce recurrent PPV-related issues. However, long-term follow-up results are needed to evaluate the advantages and disadvantages in a larger case series.

Etiology of Inguinal Hernias: A Comprehensive Review

Background

The etiology of inguinal hernias remains uncertain even though the lifetime risk of developing an inguinal hernia is 27% for men and 3% for women. The aim was to summarize the evidence on hernia etiology, with focus on differences between lateral and medial hernias.

Results

Lateral and medial hernias seem to have common as well as different etiologies. A patent processus vaginalis and increased cumulative mechanical exposure are risk factors for lateral hernias. Patients with medial hernias seem to have a more profoundly altered connective tissue architecture and homeostasis compared with patients with lateral hernias. However, connective tissue alteration may play a role in development of both subtypes. Inguinal hernias have a hereditary component with a complex inheritance pattern, and inguinal hernia susceptible genes have been identified that also are involved in connective tissue homeostasis.

Conclusion

The etiology of lateral and medial hernias are at least partly different, but the final explanations are still lacking on certain areas. Further investigations of inguinal hernia genes may explain the altered connective tissue observed in patients with inguinal hernias. The precise mechanisms why processus vaginalis fails to obliterate in certain patients should also be clarified. Not all patients with a patent processus vaginalis develop a lateral hernia, but increased intraabdominal pressure appears to be a contributing factor.

Sarco(endo)plasmic reticulum and plasmalemmal Ca(2+)-ATPase activities in cremaster muscles and sacs differ according to the associated inguinal pathology

Sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) and plasmalemmal Ca(2+)-ATPase (PMCA) activities in cremaster muscles and sacs, which have been subjected to different autonomic tonuses, were determined and compared. Samples of cremaster muscles and sacs associated with male or female inguinal hernia, hydrocele or undescended testis were obtained from children during operations and activities of SERCA and PMCA were determined. While highest SERCA and PMCA activities were encountered among cremaster muscles and sacs associated with undescended testis, least activities were encountered among structures associated with hydrocele. The alterations in SERCA and PMCA activities in cremaster muscles associated with undescended testis appear to reflect the attempts at maintaining the levels of cytosolic calcium. Despite similar total calcium contents, lower SERCA and PMCA activities were found in sacs associated with hydrocele compared to those associated with undescended testis suggest a difference among the levels of cytosolic calcium.

Hernias and Ewing's sarcoma family of tumours: a pooled analysis and meta-analysis

BACKGROUND

Ewing's sarcoma family of tumours has been associated with a history of hernia and with a parental occupation of farming. However, the causes of these tumours remain unknown. We therefore aimed to investigate the association between hernia and Ewing's sarcoma family of tumours.

METHODS

We did a pooled analysis of two case-control studies and a meta-analysis of three case-control studies of Ewing's sarcoma family of tumours that had adequate information on history of hernia. The primary endpoint was development of a tumour from the Ewing's sarcoma family. 138 patients with such a tumour and 574 controls were included in the pooled analysis, and 357 patients with these tumours and 745 controls were included in the meta-analysis. Risk was assessed by an odds ratio (OR) and 95% CI by use of multivariate analysis with unconditional logistic regression for the pooled analysis and random effects model for the meta-analysis.

FINDINGS

Pooled analysis showed that children with Ewing's sarcoma family of tumours were more likely to have had an umbilical hernia than were controls (odds ratio [OR] 3.3 [95% CI 1.3-8.0]). Meta-analysis showed that children with Ewing's sarcoma family of tumours were more likely to have had a hernia (3.2 [1.9-5.7]).

INTERPRETATION

Ewing's sarcoma family of tumours and hernias (particularly inguinal hernias) have common embryological pathways of neuroectodermal origin, and environmental factors, such as farming, might link the two entities.

A comparative histopathological evaluation of sacs from boys and girls with inguinal hernia

The purpose of this study is to determine and to compare histopathologic alterations of hernia sacs obtained from patients with inguinal hernia with those of the peritoneal tissue from patients operated on for other abdominal disorders. Samples were obtained from 42 pediatric patients with uni- or bilateral hernias, and from 30 pediatric control patients without hernia. Sections were stained with hematoxylin-eosin, Gomori's trichrome, and Gomori's reticulin. Furthermore, they were immunohistochemically stained with anti-synaptophysin for the quantification of neural structures. All the slides were examined for six parameters, including variations in tissue and collagen types, the presence of inflammation and proliferation of vessels, neural plexus, and mesothelial cells. The results were evaluated statistically using the independent T-test and the Mann-Whitney-U test. Parametric tests revealed a higher presence of large neural plexus (p = 0.003), increased proliferation of mesothelial cells (p = 0.009), and hypervascularization (p = 0.003) in sacs of the hernia group. There were also major changes that were dependent on the sex of the patients. Most part of hernia sacs tissue was found to be fibrous and adipose in most boy patients, but was fibro-muscular in girls with inguinal hernia (male/female p = 0.03), while the tissues were fibro-adipose in both sexes in the control group (inguinal hernia/control p = 0.016). Similarly, vascular proliferation was mainly encountered in hernia sacs of girls (p = 0.013). These features were not observed in the control groups. Therefore, on the basis of sex, we determined whether or not these findings could indicate the difference between the etiopathologic mechanisms of inguinal hernias. Furthermore, we went into the question of whether or not the comprehensive examination of hernia sacs sufficed to enlighten the etiology of hernias.

The role of smooth muscle cell differentiation in the mechanism of obliteration of processus vaginalis

BACKGROUND/PURPOSE

Development of indirect inguinal hernia and hydrocele in childhood is readily explained by the persistence of smooth muscle component around the processus vaginalis (PV) after the descent of the testis into the scrotum. The aim of this study was to investigate the expression of smooth muscle myosin heavy chain (SM MHC) isoforms as the markers of smooth muscle cell (SMC) differentiation in childhood inguinal hernia and hydrocele and in age-matched controls.

METHODS

The authors analyzed sacs from patients with inguinal hernia (male, 10; female, 10) and hydrocele (n = 10) immunohistochemically using monoclonal antibodies against alpha-smooth muscle actin, SM1, SM2 and SMemb. Peritoneal samples (male, 5; female, 5) obtained from age-matched patients served as controls. Immunostaining was evaluated with semiquantitative scoring and chi2 test.

RESULTS

The expression pattern of SM MHC isoforms did not differ among sacs obtained from female inguinal hernia when compared with that of controls. However, strong expression of SMemb within the sac walls of male inguinal hernia and SM1 in hydrocele groups were observed.

CONCLUSIONS

Our results indicate that SMC differentiation may play an important role in the obliteration of processus vaginalis in male inguinal hernia and hydrocele after the descent of the testis.

Do alterations in collagen synthesis play an etiologic role in childhood inguinoscrotal pathologies: an immunohistochemical study

BACKGROUND/PURPOSE

Previous findings have suggested that the development of adult inguinal hernias could be related to alterations in fibrillar collagen synthesis in the hernial sac as a decrease in the ratio of the relative amounts of type I/III collagen. The aim of this study was to investigate whether an alteration in type I and type III collagen synthesis was associated with the development of childhood inguinoscrotal pathologies.

METHODS

The authors analyzed sacs from patients with inguinal hernia (n = 20), hydrocele (n = 10) and undescended testis (n = 10) immunohistochemically using monoclonal antibodies against alpha-smooth muscle actin, collagen type I and III. Peritoneal samples (n = 10) obtained from age-matched patients served as controls. Immunostaining was evaluated by semiquantitative scoring and chi2 test.

RESULTS

The expression pattern of type I and III collagen did not differ among sacs obtained from patients with inguinal hernia, hydrocele, and undescended testis when compared with that of controls. However, strong expression of type III collagen was observed in the hernial sacs of right-sided male inguinal hernia compared with left side.

CONCLUSIONS

Although altered collagen synthesis was reported to play an important role in the development of adult inguinal hernias, our results indicate that a pivotal role in childhood inguinoscrotal pathologies is not likely.

Ultrastructural deficiency in autonomic innervation in cremasteric muscle of boys with undescended testis

BACKGROUND/PURPOSE

The cremaster muscles (CM) associated with undescended testis reveal neurogenic alterations that mainly affect type 2 fibers. The ultrastructure of CM has been evaluated to define if further evidence to explain the alterations could be identified.

METHODS

CM of 8 boys with inguinal hernia and 8 boys with undescended testis at similar ages were biopsied. Samples were processed for electron microscopic evaluations. Semithin and thin sections were examined under an electron microscope.

RESULTS

The CM associated with inguinal hernia showed normal ultrastructure. However, some alterations were encountered in CM associated with undescended testis. Unmyelinated fibers were diminished in number, and myelinated fibers were outnumbering the unmyelinated fibers. Marked disorientation of myofibers, redundant sarcolemma, empty sleeves of basal lamina, disarray of myofibrils, densely packed myofilaments, Z disk streaming, dilated sarcoplasmic reticulum, and dense-irregularly shaped mitochondria were repeatedly encountered. Satellite cells appeared inactive. Most of the fibers were contracted.

CONCLUSIONS

The decrease in number of unmyelinated fibers appears to represent a decrease in autonomic nerve fibers. The alterations within muscle fibers may reflect a deficiency in autonomic innervation. Autonomic nervous system is highly responsive to circulating androgens. Factors decreasing the vulnerability of autonomic nervous system against androgenic effects may result in a CM with neurogenic alterations, thus inhibiting testicular descent. J Pediatr Surg 36:573-578.

Excessive sac pressures: the pathogenesis and innocence of hydroceles in children

OBJECTIVE

To determine whether paediatric hydroceles result entirely from a small-calibre patent processus vaginalis, allowing free communication between the abdominal cavity and hydrocele sac, or whether there are other mechanisms.

PATIENTS AND METHODS

Twenty-five hydroceles were studied prospectively in 24 boys (aged 18-132 months). Consent for the intraoperative measurements was obtained before surgery. The hydrocele was repaired under general anaesthesia with endotracheal intubation, using a standard approach, taking care not to open the sac during mobilization. Intra-abdominal pressures during surgery were measured indirectly via a nasogastric tube after gastric decompression. The pressure in the sac was measured via a 20 G intravenous cannula inserted via a purse-string suture. The relative pressure was then calculated by subtracting the intra-abdominal from the sac pressure. The effects of age and laterality were evaluated.

RESULTS

The median (range) intra-abdominal, sac and relative pressures were 8 (2-18), 11 (3-30) and 4 (3-30) cmH2O, respectively. The sac pressure in the sac was greater than the intra-abdominal pressure in 17 of 25 (68%; P = 0.004) patients. Age or laterality had no significant influence on any of the pressures.

CONCLUSIONS

These results suggest that in a significant proportion of hydroceles in children the pressures are higher than the intra-abdominal pressure. Therefore, they cannot be explained simply as a freely communicating, narrow-calibre processus. In addition, the pressures may reach levels which are potentially damaging to the testis.

Myofibroblasts defined by electron microscopy suggest the dedifferentiation of smooth muscle within the sac walls associated with congenital inguinal hernia

OBJECTIVE

To ascertain the presence of myofibroblasts in sacs associated with inguinal hernia in children, through an ultrastructural evaluation using electron microscopy.

MATERIALS AND METHODS

Sacs were obtained from 10 boys and 10 girls (of similar age, approximately 45 months) with inguinal hernia and processed for electron microscopy. Thin sections were examined specifically for the presence of myofibroblasts.

RESULTS

The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the gender of origin.

CONCLUSION

The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth muscle and thus such cells within the sac walls seem to originate from the smooth muscle, reflecting the dedifferentiation of smooth muscle. This dedifferentiated state may represent attempted apoptosis, which usually causes the disappearance of the smooth muscle and obliteration of the processus vaginalis after the descent of the testis into the scrotum.