The Impact of Micropapillary Component Ratio on the Prognosis of Patients With Invasive Micropapillary Breast Carcinoma.

Background and Objectives: Invasive micropapillary carcinoma (IMPC) of the breast is a rare and aggressive variant of invasive ductal carcinoma characterized by high-grade lymphovascular invasion and high rates of nodal metastasis. The prognostic significance of the micropapillary component (MC) ratio that constitutes this aggressive variation is controversial. In this study, we aimed to investigate the effect of the MC ratio on the prognosis of these patients. Methods: The data of 47 patients with IMPC were retrospectively reviewed. Patients were divided into two groups: MC ratio of 10-75% (Group 1) and greater than 75% (Group 2). The demographic characteristics of the patients, histopathologic features of the tumors, and survival rates were compared. Results: We detected no significant difference in demographic characteristics between groups 1 and 2 (p = 0.21). No significant difference was detected in terms of tumor diameter, lymph node metastasis, lymphovascular invasion, histologic grade, multicentricity, local recurrence, distant metastasis, and overall survival. Conclusion: In the micropapillary subgroup of invasive ductal carcinoma, although positive receptor characteristics are directly proportional to the increase in MC ratio, recurrence and survival rates are not affected by micropapillary component level.