Background: The objective of this study was to obtain detailed anatomical information about the lateral lymph nodes, in order to determine whether they might play a role in presacral local recurrence of rectal cancer after total mesorectal excision without lateral lymph node dissection.
Methods: Ten serially sectioned human fetal pelvises were studied at high magnification and a three-dimensional reconstruction of the fetal pelvis was made.
Results: Examination of the histological sections and the three-dimensional reconstruction showed that lateral lymph node tissue comprises a major proportion of the pelvic tissue volume. There were no lymph nodes located in the presacral area. Connections between the mesorectal and extramesorectal lymph node system were found in all fetal pelvises, located below the peritoneal reflection on the anterolateral side of the fetal rectum. At this site middle rectal vessels passed to and from the mesorectum, and branches of the autonomic nervous system bridge to innervate the rectal wall.
Conclusion: The findings of this study support the hypothesis that tumour recurrence might arise from lateral lymph nodes.