BACKGROUND: To identify possible micrometastases by immunohistochemistry, to verify their morphological characteristics in regional lymph nodes and to evaluate their influence on the survival of patients with colorectal carcinoma that had been extirpated in a curative intent. METHOD: A study was made of 51 patients with colorectal carcinoma in stages A (13 patients) and B (38 patients), according to Dukes classification. A total of 501 lymph nodes previously considered free by conventional histopathological examination were submitted to immunohistochemical study using the technique of AE1/AE3 anticytokeratin monoclonal antibodies for the detection of neoplastic epithelial cells in their interior. Three serial sections, with three slices per section, with 4 millimicron were prepared from each slice. RESULTS: Neoplastic cells were identified in six patients (11.7%) at stage B in the Dukes classification, in seven lymph nodes of the mesocolon (1.4%) previously considered free of neoplasia by conventional histopathological examination. In one case, micrometastasis was represented by a cell agglomeration, while in the other five cases, it was made up of isolated cells. Survival of patients with extirpated colorectal cancer with lymph node metastases was less than for the group of patients with involved lymph nodes, although without presenting a significant difference. CONCLUSIONS: The immunohistochemical method may be employed for the detection of neoplastic cells in lymph nodes previously considered free by conventional histopathological examination. The presence of a micrometastasis in regional lymph nodes did not significantly influenced survival of patients who had colorectal carcinoma extirpated with curative intent.
Colonic neoplasms; Prognosis; Lymph nodes; Neoplasm staging; Immunohistochemistry
