Background and objectives: Mesorectal tissue seems to be an ideal substrate for the spreading of tumors. The aim was to study the distribution of mesorectal neoplastic foci, examine occurrence of circumferential margin involvement and investigate micrometastasis of the lymph nodes.
Methods: A large slice technique, combined with tissue microarray, was used in the pathologic study of 31 specimens operated on following the principles of total mesorectal excision (TME).
Results: Three hundred and forty-nine mesorectal neoplastic foci were examined from 18 specimens. Almost one third of them were in the outer layer of mesorectum. Concerning position of primary tumor, ipsolateral neoplastic foci were significantly more than contralateral neoplstic foci. Twelve specimens were diagnosed to have circumferential margin involved. Nine hundred and ninety-two lymph nodes were harvested with 148 involved by tumor. No significant difference in occurrence of micrometastasis was observed among tumors of different stage.
Conclusion: Combination of large slice and tissue microarray provided a more detailed method in studying the spread of rectal cancer. Complete excision of the mesorectum with fascia propria circumferentially intact is essential since there is an outer scattering and lateral discrepancy for neoplastic foci distribution. Circumferential margin involvement and micrometastasis observed suggested adoption of preoperative and/or postoperative radiochemotherapy.
Copyright 2005 Wiley-Liss, Inc.