The mechanism of spontaneous recanalization of human vasectomized ductus deferens.

ABSTRACT

The longitudinal and serial histologic sections of spontaneously recanalized ductus deferens and those of the contralateral ductus deferens displayed many tortuous epithelial tubules growing from the mucosal epithelium of distal stumps intruding into the fibrous scar tissue toward proximal stumps. One of the growing gland-like tubules might perform the spontaneous recanalization.

ABSTRACT

PIP Many cases of spontaneous ductus deferens recanalizations have been recorded in the last few years, since vasectomy became an effective and safe male contraceptive method. The exact mechanism of spontaneous recanalization is unknown. The patient, a 46-year old man, declared that his wife became pregnant 3 years following his vasectomy. Examination of the patient revealed a nodule that was 1 cm in length on the left ductus deferens 2 cm from the superior pole of the left testis. In the right ductus deferens a lesser nodule was seen--0.4 cm long 2 cm from the superior pole of the right testis. A spermiogram showed a sperm count of 39 million/ml with 70% motility at the 1st hour and normal forms. Following surgical exploration, a bilateral vasectomy with recession of 3 cm long segments, just at the sites of former vasoligations, was performed. The right and left segments were fixed in Bouin's fluid for 24 hours and embedded in paraffin wax. A dense fibrous scar tissue filled the space of 4 mm between the distal and proximal stumps. The lumen of the proximal cut end was slightly dilated and had a blind end. The lining epithelium was pseudostratified and columnar and involved some spermatozoal debris and other cells. The lumen of the distal stumps lined by some epithelia was irregular. Many tortuous blind-ended tubules lined by ciliated cubic epithelium that arose from this cut end invaded the scar tissue. The lamina propria and muscular wall were morphologically normal and ended in sudden constriction at the rim of scar tissue. A dense fibrous scar tissue filled the space of 2 mm between the distal and proximal cut ends and covered the ductus deferens on both sides. The extension was 8 mm long. The distal and proximal stumps were connected by a tortuous canal lined by pseudostratified low columnar epithelium. Close to the scar tissue, the muscular walls of distal and proximal stumps ended abruptly, and only a tortuous epithelial canal passed through the scar tissue. In sum, the longitudinal and serial histologic sections of spontaneously recanalized ductus deferens and those of the contralateral ductus deferens displayed many tortuous epithelial tubules growing from the mucosal epithelium of distal stumps intruding into the fibrous scar tissue toward proximal stumps. 1 of the growing gland-like tubules might perform the spontaneous recanalization.