Significance of accessory ductal structures in hernia sacs.

The finding of ductal structures resembling a vas deferens during pathological examination of a hernia sac specimen has significant medical and legal implications. A method of distinguishing these accessory structures from an inadvertently transected vas has been lacking and is needed. Between July 1989 and January 1990 we examined 147 hernia sacs from 105 consecutive prepubertal and adolescent boys to determine the incidence and salient histological features distinguishing these ductal structures from a true vas deferens. Luminal diameters of the ductal structures were compared with published normal age-related established vas deferens diameters and with those measured during hernia repair in 10 of our youngest patients. Among the 147 specimens 6 hernia sacs (4.1%) contained ductal structures. We found that the mean ductal diameter (0.263 mm.) was significantly smaller than that of a normal vas deferens (0.69 to 1.5 mm.). Furthermore, the surrounding mantle of tissue of these ductal structures lacked muscle tissue when studied with Masson trichrome stain. We conclude that duct diameter and trichrome staining are simple ways of differentiating these structures from a true vas deferens.