Re-fixation in a lymph node revealing solution is a powerful method for identifying lymph nodes in colorectal resection specimens

Aim: To verify an impact of a lymph node revealing solution (LRS) on the number of lymph nodes (LN) revealed in colorectal resection specimens. Material and method: Fifty-nine cases of rectosigmoid carcinomas divided into two subgroups-stage pT2&3 (20 cases) and ypT2&3 (with pre-operative radiotherapy-39 cases)-were formalin fixed for 42-72 h, serially sectioned and re-fixed in LRS containing ethanol, diethyl ether, glacial acetic acid, and formalin for 24 h. The number of LNs was matched to a control group consisting of 34 cases of colorectal carcinoma, 14 pT2&3 and 20 ypT2&3 rectosigmoid carcinomas examined routinely. Results were statistically tested by Student's t-test. Results: In the study group the total number of revealed LNs was 869, range 1-48, average 14.7 per specimen, median 15. In the control group the number of LNs was 200, range 0-13, average 5.9 per specimen, median 6. The difference between the study and the control group was statistically significant (P=0.05). Conclusion: Using LRS leads to a significant increase in the number of revealed LNs in colorectal resection specimens and makes it possible to find more than 12 LNs in a majority of stage pT2 and pT3 adenocarcinomas. (C) 2006 Elsevier Ltd. All rights reserved.