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.