A comparative histopathologic and immunohistopathologic evaluation of cremaster muscles from boys with various inguinoscrotal pathologies

Aim: It has been hypothesized that the cremaster muscle (CM) might play a p art in the pathogenesis of various inguinoscrotal pathologies such as undes cended testis and hernia. A prospective study was carried out to determine if CM of boys with hydrocele, inguinal hernia, and undescended testis revea l 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 fr om patients undergoing laparotomy (3) were obtained. The biopsies were froz en in isopentane-cooled liquid nitrogen, cut in 6 micron sections and store d at -80 degreesC until processed. Sections were stained by hematoxylin-eos in, modified Gomori-trichrome, PAS, Oil Red-O, NADH, SDH and COX. All speci mens were evaluated for seven parameters including Variation in fibre size, presence of central nucleus, endomysial fibrosis, inflammation, presence o f basophilic fibres, increase in perimysial connective tissue, and variatio n in fibre size between fascicules. The specimens were also evaluated for b eta-spectrin, laminin alpha-1 chain, laminin alpha-2 chain, 43 kd distrogly can, and fetal myosin by immunofluorescence. The presence of each parameter was compared, individually and in combination, according to the ages and u nderlying 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 acid increas e in perimysial connective tissue were found in all but one CM from a patie nt with hernia. The presence or absence of parameters did not differ accord ing to age. Comparison of the groups with inguinal hernia and undescended t estis for each of the individual parameters did not reveal significant diff erences. However, the presence of four or more parameters in each CM was mo re 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, r egardless of origin, revealed normal sarcolemmal and basal laminal staining s, 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 h ernia. Conclusion: The CM of patients with inguinal hernia, hydrocele, and undesce nded testis reveal histopathological alterations. Furthermore, CM from pati ents with undescended testis reveal more profound alterations. Whether thes e alterations reflect a primary muscle pathology or a defect in innervation or changes secondary to inguinoscrotal pathology requires further study.