[309] Does the Presence of Invasive Micropapillary Carcinoma Component Truly Affect the Lymph Node Status of Invasive Ductal Carcinoma? Review of 263 Cases of pT1c Breast Cancer

Sanae Yamazaki, Eiichi Konishi, Nobuhiko Shinkura, Tetsuya Taguchi, Akio Yanagisawa. Kyoto Prefectural University of Medicine, Kyoto, Japan; Kyoto Breast Center Sawai Memorial Clinic, Kyoto, Japan

Background: Invasive micropapillary carcinoma (IMPC) of the breast is thought to have frequent lymph node metastasis and result in a worse outcome. IMPC may be found as a component of invasive ductal carcinoma, not otherwise specified (IDCNOS). However, whether the presence of even a minor IMPC component, e.g., a single micropapillary nodule affects the lymph node status of IDCNOS, or not, is still unclear, especially when the tumor size (pT) is the same. We elucidate the lymph node status of pT1c IDCNOS cases that have IMPC as a component and compare the lymph node status between the cases with and without IMPC component.
Design: Two hundred and sixty three surgical cases of pT1c IDCNOS, were studied. None of the patients had any neoadjuvant chemotherapy and/or hormonal therapy. We reviewed all HE slides to detect the cases with IMPC component. For the detected cases, we performed immunohistochemistry against EMA (epithelial membrane antigen) and MUC1 (Muc-1 glycoprotein), in order to elucidate whether the expression was noted at the reversed apical membrane or not. When the expression of EMA and/or MUC1 was found at the whole circumference of at least one tumor nest, we regarded it as having IMPC component. Lymph node status was checked by reviewing the HE slides. Nodes containing only isolated tumor cells were excluded from the positive lymph node status group.
Results: We regarded 64 IDCNOS cases as having IMPC as a component by reviewing HE slides. Among these, 35 cases showed the reversed apical expression of EMA and/or MUC1 at the whole circumference of at least one tumor nest. The lymph node status of both the cases with and without IMPC component is summarized in Table 1. Chi-square test revealed statistically significant difference between the two groups (p=0.011). IDCNOS with IMPC component had the lymph node metastasis more frequently than IDCNOS without it.

Table 1. Correlation between the presence of IMPC component and lymph node status
 Node (+)Node (-) 
IMPC component (+)132235
IMPC component (-)42186228
 55208263
IMPC: invasive micropapillary carcinoma, p=0.011 (Chi-square test)


Conclusions: When IMPC is noted as a component in pT1c IDCNOS, its presence affects the lymph node status, even when the IMPC component is minimal. We should account for the presence of IMPC, even if it is small amount.
Category: Breast

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 40, Wednesday Morning

 

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