Clinicopathological significance of invasive micropapillary carcinoma component in invasive breast carcinoma

Abstract

Invasive micropapillary carcinoma (IMP) of the breast is a rare variant of invasive breast carcinoma and most cases of IMP are associated with nodal metastasis and lymphatic invasion. Lesions composed of an IMP component alone are rare and almost always coexist with other pathological components. However, few reports have documented IMP along with its proportion and the coexistent pathological type. We analyzed the total 486 breast cancer lesions operated in our hospital in 1998. We classified the lesions into five groups by the proportion of the IMP component in each lesion. Then we evaluated the incidence of nodal metastasis and lymphatic invasion in each group. The incidence of the invasive carcinoma containing any IMP components was 8.4%. The incidence of nodal metastasis and lymphatic invasion in lesions with an IMP component were significantly higher than that in those with no IMP. No correlation was seen between the incidence of nodal metastasis and the coexistent pathological type, shape of tumor clusters, nuclear grade and the expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 and gross cystic disease fluid protein-15 in IMP components. The presence of IMP components was a significant predictive factor for nodal metastasis, even if it is detected in only a small proportion of the tumor.

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

“…However, no consensus has yet been reached on the proportion of the IMPC component in a tumor that is required for its pathological diagnosis [13]. In addition, previous studies did not find a direct correlation between the ratio of the IMPC component and either lymph node involvement or survival [9], [17]. Furthermore, pathology data addressing histological grade and Ki-67 were excluded from the current analysis, but these variables may have an effect on survival.…”

“…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 Breast: An Update

“…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.…”

“…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.…”

Cytological features of pure micropapillary carcinoma of various organs: A report of eight cases

“…In addition, similar morphological characteristics of MPC are rarely detected in other non-ovarian sites, such as the breast, urinary bladder, lung, parotid glands and colon (2–7). In anatomical locations other than the ovaries, MPC exhibits an aggressive course and generally accompanies the primary neoplasm of the organ of its origin (2).…”