【Abstract】Objective To investigate the detection and significance of micrometastasis in lymph nodes of periampullary carcinoma. MethodsThe immunoreactivity of CK19, CK7 and CK18 in 220 lymph nodes from 60 patients who had been carried out radical resection of periampullary carcinoma were revealed by immunohistochemical method. Combining with clinical data and the followup result discussion and analysis were made. All the lymph nodes collected from January 1997 to August 2004 in this hospital were examined to be nonlymphonodus metastasis by histological HE stain. The criterion of positive CK was established and micrometastasis will be diagnosed if CKs revealed to be positive combining with the morphological changes of lymph node tissue through the observation of microscope. ResultsFortythree of 220 lymph nodes of periampullary carcinoma had been micro metastasized. The detection rates of micrometastasis were 19.55%（43/220）， 14.55%（32/220）and 11.36%（25/220） with CK19，CK7 and CK18 antibody, respectively, which meant that CK19 were better than CK18 for detection of micrometastasis. Detection rates of CK7， CK19 were higher in Ⅲ， Ⅳ stage than inⅠ， Ⅱ（P＜0.05）, whereas it had no relationship with gender, age and tumor differentiation degree. The oneyear survival rate for micrometastasis patients was lower than nonmicrometastasis patients’ (P＜0.05). Conclusion Micrometastasis of periampullary carcinoma may be the early stage of tumor metastasia. The CK antibodies are significant levels to detect micrometastasis of periampullary carcinoma and to guide the clinical treatment and prognostic judgment.