Aim: It has been hypothesized that the cremaster muscle (CM) might play a part in the pathogenesis of various inguinoscrotal pathologies such as undescended testis and hernia. A prospective study was carried out to determine if CM of boys with hydrocele, inguinal hernia, and undescended testis reveal any histopathological and immunohistopathological alterations.
Methods: Samples of CM from 29 patients presenting with inguinal hernia (15), undescended testis (9), and hydrocele (5), and CM from autopsies of boys without inguinal pathology (2), and samples of internal oblique muscles from patients undergoing laparotomy (3) were obtained. The biopsies were frozen in isopentane-cooled liquid nitrogen, cut in 6 micron sections and stored at -80 degrees C until processed. Sections were stained by hematoxylin-eosin, modified Gomori-trichrome, PAS, Oil Red-O, NADH, SDH and COX. All specimens were evaluated for seven parameters including variation in fibre size, presence of central nucleus, endomysial fibrosis, inflammation, presence of basophilic fibres, increase in perimysial connective tissue, and variation in fibre size between fascicules. The specimens were also evaluated for beta-spectrin, laminin alpha-1 chain, laminin alpha-2 chain, 43 kd distroglycan, and fetal myosin by immunofluorescence. The presence of each parameter was compared, individually and in combination, according to the ages and underlying pathologies.
Results: None of the internal oblique muscles were positive for any of the seven parameters. Only one of the two CM obtained during autopsy revealed a slight variation in fibre size. However, fibre size variation and increase in perimysial connective tissue were found in all but one CM from a patient with hernia. The presence or absence of parameters did not differ according to age. Comparison of the groups with inguinal hernia and undescended testis for each of the individual parameters did not reveal significant differences. However, the presence of four or more parameters in each CM was more commonly encountered among patients with undescended testis compared to patients with hernia (p < 0.05). The CM of patients with hydrocele suggested similar findings to patients with inguinal hernia. All of the specimens, regardless of origin, revealed normal sarcolemmal and basal laminal stainings, and fetal myosin was expressed in only two specimens which were obtained from an internal oblique muscle and the CM of a patient with an inguinal hernia.
Conclusion: The CM of patients with inguinal hernia, hydrocele, and undescended testis reveal histopathological alterations. Furthermore, CM from patients with undescended testis reveal more profound alterations. Whether these alterations reflect a primary muscle pathology or a defect in innervation or changes secondary to inguinoscrotal pathology requires further study.