Population-based comparison of prognostic factors in invasive micropapillary and invasive ductal carcinoma of the breast

BACKGROUND: Invasive micropapillary carcinoma (IMPC) is a variant of breast carcinoma with a higher propensity for lymph node metastases compared with invasive ductal carcinoma (IDC). METHODS: Retrospective analysis of 636 IMPC and 297 735 IDC cases in the Surveillance, Epidemiology and End Results database comparing disease-specific survival (DSS) and overall survival (OS) between IMPC and IDC. RESULTS: A higher percentage of IMPC cases (52.0%) had nodal metastases compared with IDC cases (34.6%). The 5-year DSS and OS for IMPC was 91.8% and 82.9%, respectively compared with 88.6% and 80.5% for IDC, respectively. For both IMPC and IDC, oestrogen-receptor positivity was associated with better survival, while having four or more positive lymph nodes or larger tumour size correlated with worse survival. Radiotherapy provided a survival benefit for both histological types. CONCLUSIONS: Despite IMPC's higher propensity for lymph node metastasis, IMPC has DSS and OS that compare favourably with IDC

Invasive Micropapillary Carcinoma of the Breast: MR Imaging Findings

OBJECTIVE: To analyze the magnetic resonance (MR) imaging findings of invasive micropapillary carcinoma of the breast. MATERIALS AND METHODS: MR images were retrospectively evaluated in 14 patients (age range: 37-67, mean age: 49 years) with pathologically confirmed invasive micropapillary carcinoma of the breast. The enhancement type (mass/non-mass), shape, margin, contrast enhancement, and time-intensity curve pattern on the dynamic study were correlated with the histopathologic features. Associated findings, such as edema, nipple change, skin change and enlarged axillary lymph nodes were also studied. RESULTS: The most common features of the masses were irregular shape (12 of 14 patients, 85.8%) and irregular or spiculated margin (11 of 14 patients, 78.7%). The contrast enhancement was heterogeneous in 11 patients (78.7%), rim enhancement in 2 cases (14.2%), and homogeneous in one patient (7.1%). The predominant kinetic pattern was rapid increase (14 of 14, 100%) in the initial phase and washout (11 of 14, 78.7%) in the delayed phase. Associated non-mass like enhancement was shown in 4 patients, representing ductal carcinoma in situ. MR imaging helped detect additional sites of cancer other than the index lesion in 3 patients (21.4%). Enlarged axillary lymphadenopathy was identified in 7 of the 14 patients (50%). CONCLUSION: Invasive micropapillary carcinoma appears as a mass with an irregular shape, irregular or spiculated margin and heterogeneous enhancement on MR imaging. Though these findings are not specific and are also observed with other breast malignancies, invasive micropapillary carcinoma frequently showed multiple lesions, accompanying non-mass enhancement and axillary lymph node enlargement