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

Objective To ascertain the presence of myofibroblasts in sacs associated wi th inguinal hernia in children, through an ultrastructural evaluation using electron microscopy Materials and methods Sacs were obtained from 10 boys and 10 girls (of simi lar age, approximate to 45 months) with inguinal hernia and processed for e lectron microscopy. Thin sections were examined specifically for the presen ce of myofibroblasts. Results The ultrastructural evaluation showed myofibroblasts with classical electron microscopic features within all of the sacs, regardless of the ge nder of origin. Conclusion The persistence of smooth muscle hinders the obliteration of the processus vaginalis; myofibroblasts are found in association with smooth m uscle and thus such cells within the sac walls seem to originate from the s mooth muscle, reflecting the dedifferentiation of smooth muscle. This dedif ferentiated state may represent attempted apoptosis, which usually causes t he disappearance of the smooth muscle and obliteration of the processus vag inalis after the descent of the testis into the scrotum.