Invasive Micropapillary Carcinoma of the Breast : Clinicopathologic Study of 62 Cases of a Poorly Recognized Variant With Highly Aggressive Behavior

Abstract

We report 62 cases of invasive micropapillary carcinoma of the breast characterized by delicate pseudopapillary structures lacking a fibrovascular core and by tubuloalveolar structures freely floating in clear, empty spaces. All patients but 1 were women (median age, 57 years; range, 25-89 years). Tumor size ranged from 0.7 to 10 cm (median, 2.8 cm); 54 (87%) were grade 3. Psammoma bodies were identified in 29 (47%). Focal to massive lymphatic permeation was present in 39 (63%). Architectural features were retained in the node metastases, dermal lymphatics, and recurrences. Fifty-six patients (90%) had metastatic axillary nodes: 18 tumors were estrogen receptor-positive (32%); 11 were progesterone receptor-positive (20%); HER2/neu was overexpressed in 53 (95%) and p53 in 39 (70%). A peculiar immunoreactivity for MUC1 limited to the cytoplasmic membrane oriented toward the stroma and an absence of immunoreactivity for E-cadherin in the same side of the cytoplasmic membrane indicated inversion of cell polarization and a disturbance in the cell adhesion molecules. Of 41 patients with available follow-up, 29 (71%) had local recurrence (mean, 30 months) and 20 (49%) died of disease. These results underscore the aggressive behavior and poor prognosis of this breast carcinoma variant. Aggressive preoperative neoadjuvant chemotherapy should be considered.

Incomplete inside-out growth pattern in invasive breast carcinoma: association with lymph vessel invasion and recurrence-free survival

“…IMPC generally shows frequent LVI and lymph node metastasis [13][14][15][16][17]; however, our 10 IMPC cases showed relatively low frequencies of LVI (50%) and nodal involvement (30%). The reason for this is unclear, but it may be related to the small number of cases and the histologic features [22].…”

“…It is characterized by aggregates of small clusters of tumor cells lying within clear stromal spaces resembling dilated vascular channels, reversed polarity, an "inside-out" micropapillary morphology, and frequent LVI and lymph node metastasis [13][14][15][16][17]. The term "inside-out growth pattern" and its clinicopathologic significance in breast cancer were first introduced by Peterse [18].…”

Micropapillary pattern and grade of stromal invasion in pT1 adenocarcinoma of the lung: usefulness as prognostic factors

“…For example, it is reported that MUC1 expression was predominantly demonstrated in the stroma-facing surface of the micropapillary cell clusters in micropapillary pattern-positive breast and colon carcinomas, and that this expression pattern indicates inversion of cell polarization as MUC1 is a glycoprotein normally located in the apical cell surface of normal glandular epithelium. [31][32][33] It has been speculated that the presence of MUC1 in the stroma-facing surface of micropapillary cell clusters may lead to their inverted morphology and detachment of cells from the stroma based on the known function of MUC1 that inhibits the interaction between cell and stroma. [31][32][33] Micropapillary pattern and lung adenocarcinoma invasion T Kawakami et al…”

“…[31][32][33] It has been speculated that the presence of MUC1 in the stroma-facing surface of micropapillary cell clusters may lead to their inverted morphology and detachment of cells from the stroma based on the known function of MUC1 that inhibits the interaction between cell and stroma. [31][32][33] Micropapillary pattern and lung adenocarcinoma invasion T Kawakami et al…”

Micropapillary carcinoma: pathogenesis, histological and clinical features

“…Mitotik aktivite ise değişkenlik göstermektedir. Memenin invaziv mikropapiller karsinomlarının %42-62'sinde izlenen psammom cisimleri, akciğerin invaziv mikropapiller karsinomlarında nadir olarak görülmekte, mesane ve tükürük bezindeki olgularda ise görülmemektedir (2)(3)(4)8,11,12).…”