LYMPH NODE-REVEALING SOLUTION - SIMPLE NEW METHOD FOR DETECTING MINUTE LYMPH-NODES IN COLON-CARCINOMA

PURPOSE: Detection of metastatic lymph nodes in colon cancer is essent ial for determining stage and, thus, therapeutic modalities. However, very small lymph nodes can easily be missed during routine examination . The aim of this study is to describe a new and easy technique for de tecting tiny nodes in colonic specimens. METHODS: Thirty problematic c ases, in which an unsatisfactory number of lymph nodes was found by th e traditional method, were investigated. The entire mesocolonic fat wa s immersed for six hours in a lymph node-revealing solution (LNRS) com posed of various traditional fixatives and fatty solvents. After six h ours, the lymph nodes stood out as white, chalky nodules on the backgr ound of yellow fat. They were then excised, processed. and stained. RE SULTS: Total number of lymph nodes found by the traditional method in the 30 cases was 88. After LNRS, 258 additional lymph nodes, measuring from 0.5 to 7 mm in largest diameter, were found. Of the 12 cases in which no lymph nodes were found by the traditional method, 8 became N0 and 4 became N1. Of the 14 cases first classified as N0, 4 became N1; of the 4 classified at first as N1, 2 became N2 after LNRS. Upstaging from Dukes B to C occurred in eight cases. Quality of the sections an d histochemical and immunohistochemical stains after LNRS was similar to that of formalin-fu;ed tissues. CONCLUSIONS: LNRS is an easy, rapid , and inexpensive technique for detecting very small lymph nodes. Thes e may contain metastases, a fact that changes the stage of disease and influences the mode of therapy.