Invasive Micropapillary Carcinoma of the Breast: A Clinicopathologic Study of 103 Cases of an Unusual and Highly Aggressive Variant of Breast Carcinoma

Abstract

Invasive micropapillary carcinoma (IMPC) of the breast is an uncommon, highly aggressive breast cancer that may occur in pure and mixed forms. Our aim in this study is to investigate the relationship between clinical, histopathologic, and immunohistochemical features of pure and mixed IMPC cases diagnosed and treated at our institution. One hundred and three IMPC cases diagnosed at our institution over a period of 19 years have been selected. Clinical, histopathologic features, as well as hormone status and c-erb-B2 overexpression of tumors were re-evaluated. Mann-Whitney U, chi-squared, Kaplan-Meier, and Fisher's exact tests were used for statistical analyses. Results were considered to be significant at p < 0.05. Twenty cases (19.4%) were pure, and 83 cases (80.6%) were mixed IMPC. The most common nonmicropapillary invasive carcinoma component in mixed cases was invasive ductal carcinoma (IDC; 78.3%). Progesterone receptor was significantly less positive in pure IMPC cases (p = 0.031). There was no statistically significant difference between the two groups, in terms of mean age of the patients (53.0 versus 52.8), mean tumor size (26.6 mm versus 27.7 mm), presence of high-grade tumor (p = 0.631), presence of sentinel lymph node (SN) metastasis (p = 1.000), axillary lymph node metastasis (p = 1.000), lymphatic invasion (p = 1.000) and blood vessel invasion (p = 0.475), c-erbB-2 overexpression of tumor cells (p = 0.616), distant metastasis (p = 0.549), or overall survival (p = 0.759). The local recurrence rate of the two groups was not statistically significant either (16.7% versus 4.3%). However, local recurrence was detected 12% more commonly (p = 0.100), and ~8 months earlier (p = 0.967) in pure IMPC cases, compared to mixed cases. In addition, presence of local recurrence was found to be statistically significantly associated with estrogen receptor (ER) status (p = 0.004), progesterone receptor (PR) status (p = 0.001), and c-erb-B2 overexpression (p = 0.016) in all patients. Overall survival rate was significantly associated with ER staining of the tumor (log-rank = 0.028). Our findings suggest that hormone receptor negativity may explain the more aggressive behavior of pure IMPC compared to mixed cases. Besides, longer survival period of patients with ER positivity, and the relationship of hormone status and c-erb-B2 overexpression and local recurrence further support favorable prognostic value of hormone receptors in invasive breast cancer.

Invasive Micropapillary Carcinoma of the Breast: An Update

“…7,[14][15][16][17]23,24,[37][38][39][40][41][42][43] One study of 624 patients with IMPC revealed a poor prognosis in the patients who had a tumor lacking in estrogen receptor expression. 7 The status of the HER2/neu protein expression or gene amplification in IMPC is not consistent in literature.…”

“…Some studies showed HER2/ neu þ rates between approximately 10% and 30%, [14][15][16]23,24 whereas others reported between approximately 50% and 80%. 34,38,41,44 Regarding the molecular classification, more cases of IMPC fall into the luminal A and luminal B subtypes than they do with IDC-NOS. 39 The features of IMPC are summarized in the Table. In addition, IMPC should be differentiated from IDC-NOS by retraction artifacts.…”

Clinico-Pathological Features and Prognosis of Invasive Micropapillary Carcinoma Compared to Invasive Ductal Carcinoma: A Population-Based Study from China

“…This carcinoma has been reported to exhibit lymphovascular invasion, lymph node metastasis, local recurrence and distant metastasis at relatively high frequencies, thus exhibiting a more aggressive behavior than invasive ductal carcinoma (IDC) [2], [3]. The rate of incidence of IMPC of the breast has been reported to range from 1.0–8.4% [4], [5], [6], [7], [8], [9], [10]. Due to the low incidence of this breast cancer variant, most studies examining IMPC have small sample sizes; the clinico-pathological characteristics and the clinical prognostic factors of invasive micropapillary carcinoma are therefore not well understood.…”

Invasive micropapillary carcinoma of the male breast: Case report and review of the literature

“…Several studies compared their cohort of IMPC patients to invasive ductal carcinoma (IDC) controls matched by disease stage and revealed a significantly higher incidence of lymph node metastasis in IMPC patients, particularly for early stage breast cancer [9][10][11][12]14,[23][24][25]28,31,32]. Yu [19-21] b Case series 68 68 NA Tressera et al [26] Case series 15 15 NA Middleton et al [22] Case series 14 14 NA Walsh and Bleiweiss [29] Case series 80 80 "Pure" (n =17), "partial" (n =63, range 5-95%) Wei et al [30] Case series 100 100 475% (n= 42), 50-75% (n=20), 25-50% (n =15), o25% (n=23) Varga et al [27] Case series 11 11 NA Li et al [18] Case series 40 40 "Pure" (n =9), "mixed" (n =31) Chen et al [14] Case series 100 100 NA Shi et al [25] Case series 188 188 "Pure" (n =27), "mixed" (n= 161) Kim et al [11] Cohort 250 38 450% (n= 17), o50% (n =21) Nassar et al [12] Cohort 1400 83 480% (n= 10), "minor proportion" (n =73) Kuroda et al [17] Cohort 671 27 "Some" De La Cruz et al [15] Cohort 1056 16 "Pure" (n =10), "mixed" (n= 6) Zekioglu et al [32] Cohort 2022 53 475% (n= 47), o75% (n =6) Pettinato et al [13] Cohort 1635 62 50-100% (n =40), 25-50% (n =12), o25% (n=10) Yu et al [31] Cohort 2753 72 470% (n= 72) Vingiani et al [28] Cohort 13,278 49 "Pure" (n =49) Paterakos et al [23] Cohort 1287 21 "Pure" (n =21) Gocke et al [10] Cohort 2718 103 "Pure" (n =20), "mixed" (n= 83) Ren et al [24] Cohort 5625 86 NA Chen et al [8,9] however no difference was seen on overall survival analysis.…”

“…Three of these reports are available in the English literature [5][6][7]. The IMPC case series currently available have included a total of 15 male patients [8][9][10][11][12][13] accounting for only 0.005% of invasive breast cancer cases. We present a case of this rare type of breast cancer diagnosed in a male patient and review the current literature to date.…”