NORMAL VAS-DEFERENS IN FETUSES WITH CYSTIC-FIBROSIS

Purpose: Infertility in patients with cystic fibrosis has been attribu ted to the congenital bilateral absence of the vas deferens. We studie d the vas deferens in cystic fibrosis fetuses to determine whether thi s condition could be related to primary developmental abnormalities or to secondary obstructions. Materials and Methods: Two cystic fibrosis male fetuses, with Delta F508+/+ and Delta F508/G542X genetic mutatio ns, were examined after abortion at 12 and 18 weeks, respectively. The lumens of the vas deferens were measured using histological serial se ctions in the 2 cystic fibrosis fetuses and in 6 control fetuses. Resu lts: The vas deferens of cystic fibrosis and control fetuses showed a similar development. The diameters of the lumens were smaller at the e xtremities than in the medial part of the duct in cystic fibrosis and in control fetuses. No epithelial necrosis, focal dilatation or fibrou s stenosis could be detected at any age. Secretions were observed in t he lumen of the vas deferens of the homozygous fetus, but no obstructi on was detected. Conclusions: The normal organogenesis of the vas defe rens, the presence of secretions filling the lumen of the Delta F508+/ + fetus and the high proportion of normal ducts reported in prepuberta l male cystic fibrosis patients suggest a mechanism of luminal obstruc tion resulting in duct atrophy and infertility in male adults with cys tic fibrosis. The term ''atresia'' or ''inspissation'' should be used in cases of congenital bilateral absence of the vas deferens associate d with cystic fibrosis mutations, whereas the term ''agenesis'' should be used for cases of congenital bilateral absence of the vas deferens associated with urogenital abnormalities in which regional defects oc cur during organogenesis.