Objective: To compare cremaster muscles (CMs) obtained from boys with inguinal hernia, hydrocele or an undescended testis and those obtained from girls with inguinal hernia, thus defining the changes associated with each clinical condition.
Materials and methods: CM samples were obtained from 26 boys and three girls with inguinal hernia, and 18 boys who had undergone surgery for an undescended testis (12) or hydrocele (six). The samples were frozen in isopentane cooled in liquid nitrogen and were processed for sectioning by cryostat. Sections (12 microm) were stained with a several histochemical stains. The presence of central nuclei, fibre splitting, basophilic fibres, fibre necrosis, inflammatory changes, small angular fibres, fibre hypertrophy, grouped atrophy, and endo- and perimysial fibrosis were evaluated. From each specimen, 200 fibres were also analysed morphometrically using a computerized image analysis system.
Results: Neurogenic changes were apparent in all the CMs from patients with an undescended testis but none of the samples obtained from girls showed any changes. While only two specimens of 26 from boys with inguinal hernia (8%) had evidence of neurological alterations, eight CM (31%) had general changes. The mean (SD) fibre diameters did not differ significantly among the groups with inguinal hernia, hydrocele and undescended testis, at 23. 0 (8.6), 24.4 (4.5) and 23.0 (10.5) microm, respectively.
Conclusion: Cremasteric muscles associated with an inguinal hernia or an undescended testis differ; neurogenic changes were detected within all the CM of boys with an undescended testis. These changes in the CM may have influenced the location of the testis.