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.

Associated malformations in delayed presentation of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Delayed presentation of congenital diaphragmatic hernia (CDH) has been considered rare, and clinical manifestations differ from the more common newborn entity. Associated malformations in late-appearing CDH have been reported in a few patients. The authors reviewed their clinical experience to catalogue the frequency and clinical importance of associated malformations in patients with late-presenting CDH. METHODS: The records of patients greater than 1 month of age with Bochdalek type CDH treated in the authors' clinic, from 1991 to 2001, were retrospectively reviewed. Twenty patients (age range, 1 month to 10 years) were included in the study. RESULTS: Associated malformations were documented in 16 of the patients (80%) and included malrotation in 12 patients, umbilical hernia in 2, pulmonary hypoplasia in 4, pulmonary sequestration in 1, gastroesophageal duplication cyst coexisting with polysplenia in 1, atrial septal defect and ventricular septal defect in 1, hydronephrosis in 1, wandering spleen in 1, talipes equinovarus in 1, and type I diabetes mellitus in 1. CONCLUSIONS: The results of this study show a significant incidence and a wide spectrum of associated malformations. These findings suggest that patients with late CDH should be evaluated carefully for additional anomalies that may help to establish correct diagnosis and treatment.