Abstract:

Objective To investigate the clinicopathologic features of invasive micropapillary carcinoma (IMPC) of breast, and explore their relationship with lymph node metastasis. Methods The clinical and pathologic features of 61 cases of IMPC of breast were retrospectively analysed, and the relationship between lymph node metastasis and factors such as T staging (tumor size), proportion of components and interstitial lymphocytic infiltration was explored. Results The rate of lymph vascular invasion of IMPC was 73.8%(45/61), and the rate of lymph node metastasis was 75.4%(46/61). There was no significant difference in rates of lymph node metastasis among patients with different T stages (P＞0.05). Besides, there was no significant difference in rates of lymph node metastasis and numbers of lymph node metastasis among different IMPC components in tumor tissues (P＞0.05 for both). However, the rate of lymph node metastasis of patients with IMPC and negative interstitial lymphocytic infiltration (54.2%) was significantly lower than that of patients with IMPC and positive interstitial lymphocytic infiltration (62.2%)(P＜0.05）. The metastatic foci in lymph node were all IMPC components or mainly IMPC components （39/43, 90.7%）. Conclusion Lymph vascular infiltration and regional lymph node metastasis are biological features of IMPC of breast. It is the characteristics of IMPC components instead of the tumor size or amount of IMPC components in the tumor that correlate with the biological behaviors of the tumor.

Key words: breast neoplasm, invasive micropapillary carcinoma, lymph node metastasis