Features Of Invasive Micropapillary Carcinoma Research Articles

Radiological characteristics of invasive micropapillary carcinoma of the breast

To analyse the various imaging features of invasive micropapillary carcinoma (IMPC), a distinct variant of breast cancer, by mammography, ultrasound, and contrast-enhanced mammography. This study included 68 female patients with histopathologically proven invasive micropapillary carcinoma who underwent mammography, ultrasound, and contrast-enhanced mammography examinations. The findings encountered by each imaging tool were analysed using the Breast Imaging Reporting and Data System (BI-RADS) lexicon. In this retrospective study, 64.7% of cases were of the pure form of IMPC. Most of the cases showed an aggressive clinical course, with lymphovascular invasion noted in 76.5% of cases, while 60.3% of cases showed associated pathological lymphadenopathy. The N3 stage was reported in 25% of cases. On analysing the mammographic and ultrasound imaging findings, a significant association between irregular shape and a non-circumscribed margin with IMPC was found. Associated calcification was noted in 47% of cases. Pathological enhancement of moderate or marked conspicuity was noted in cases that underwent contrast-enhanced mammography, with the most commonly encountered finding being enhancing irregular and non-circumscribed masses. The mammographic and ultrasound imaging features of IMPC are indistinguishable from other aggressive types of breast cancer. At contrast-enhanced mammography examination, pathological enhancement of moderate to marked conspicuity was shown in all cases. The observed strong association of IMPC with lymphovascular invasion and lymph node metastasis with higher nodal stage in this study mandate meticulous sonographic examination of the axilla, as well as the infra, and supraclavicular regions if pathological axillary lymphadenopathy was noted.

Analysis of Prognostic Factors and Construction of Prognostic Models for Invasive Micropapillary Carcinoma of the Breast

To compare and analyze the clinical characteristics of invasive micropapillary carcinoma (IMPC) of the breast (IMPC-B) and invasive ductal carcinoma (IDC) of the breast (IDC-B) and establish a prognostic model of IMPC-B. We retrospectively analyzed data for patients diagnosed with breast cancer in the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2018 and screened 581 patients with IMPC and 1325 patients with IDC. We compared age, race, laterality, tumor site, histological grade, type of surgery, radiation, chemotherapy, whether the first primary tumor, T stage, N stage, M stage, and molecular type between IMPC-B and IDC-B and draw survival curves of IMPC-B and IDC-B. The relationship between clinical factors and prognosis was investigated by univariate analysis using the Log-rank test and multivariate analysis of the Cox proportional hazards regression model. A risk scoring model was constructed based on independent risk factors to distinguish high-risk and low-risk patients; in addition, a nomogram was created to predict patient survival. There were differences between the two groups in the age of onset, race, tumor site, histological grade, type of surgery, N stage, and molecular type (p < 0.05). Overall survival was decreased in IMPC-B compared with IDC-B (p < 0.05). The prognosis of IMPC-B was significantly correlated with histological grade, whether the first primary tumor, type of surgery, radiotherapy, chemotherapy, T stage, and N stage. Based on the relationship between the above factors and overall survival prognosis, the risk score model we constructed can effectively distinguish high-risk and low-risk patients (p < 0.05). The established nomogram had better performance in predicting survival in patients with IMPC-B (C - index = 0.78). IMPC-B has a worse prognosis than IDC-B, with earlier age of onset, higher histological grade, and later N stage, and luminal breast cancer is the main type. The nomogram can well predict the prognosis of patients with IMPC-B, which has a high clinical reference value and provides a scientific basis for clinical treatment.

Abstract P3-08-31: Clinical and pathological features of invasive micropapillary carcinoma of the breast and correlation with prognosis

Abstract Background and objective: Invasive micropapillary carcinoma (IMPC) of the breast is a special variant of breast carcinoma with a unique morphology. Data about long-term outcome are conflicting and reports on stromal tumor infiltrating lymphocytes (sTILs) and their correlation with prognosis are scarce. In this retrospective cohort study we aimed to describe clinical and pathological features of IMPC, including sTILs assessment and immunohistochemistry studies, and their correlation with long-term outcome. Materials and methods: Patients with stage I-III IMPC (pure and mixed forms) who underwent upfront surgery at our institution between 2000 and 2016 were included. All patients signed informed consent. Standard clinico-pathological features and follow-up data to calculate distant relapse-free interval and breast cancer-specific survival were obtained from clinical records. Pathologic review of representative H&amp;E-slides of the resection specimens included evaluation of sTILs and assessment of the micropapillary component. Surrogate molecular subtypes were based on receptor-status and histological grade. Using tissue microarrays we assessed by immunohistochemistry the pattern of staining of P53, and scored semi-qualitatively the expression of Bcl2, PAX8 and WT1. The association between predictors and outcome is analyzed using the Fine and Gray model, accounting for other-cause death as competing event. All tests are two-sided, assuming a 5% significance level. The sample size did not allow multivariate analysis. Results: We included 111 patients (median age 61,5 years; range 33-88). Luminal surrogate subtypes were most prevalent with 51 luminal A-like, 41 luminal B-like, 12 luminal HER2+, 5 HER2+ and 2 triple negative IMPC. 89% of patients had a T1 or T2 tumor and 50% of IMPC were poorly differentiated. Lymph node involvement was present in 59% and lymphovascular invasion in 44% of cases. Adjuvant chemotherapy, radiotherapy and endocrine therapy was administered in 47%, 87% and 90% of patients, respectively. Of all cases 59% were pure IMPC. Standard clinico-pathological features were comparable between pure and non-pure IMPC. sTILs were classified as low (&amp;lt;30%), intermediate (30-50%) and high (&amp;gt;50%) in 78%, 14% and 8% of specimens respectively. Comparison between surrogate subtypes showed higher sTILs (p=0.025) and a higher likelihood of aberrant P53 expression (p&amp;lt;0.001) in HER2+ compared to luminal A-like subtype. Immunohistochemistry studies performed on 105 samples with enough material showed aberrant P53 expression in 10% and WT1 nuclear expression in 7% of cases. Pax8-staining was negative in all IMPC in this cohort. Bcl-2 expression was strongly related to all luminal subtypes (p&amp;lt;0.03). After a median follow-up of 100 months, we observed 8 distant relapses (7,2%) and 3 breast cancer-related deaths (2,7%). All events occurred in non-pure IMPC. Surrogate subtypes for patients with distant relapses where luminal A-like in 4 patients while the other subtypes where each observed in 1 patient. Five out of eight patients with distant relapse had received prior adjuvant chemotherapy. Six had lymph node involvement. Higher median sTILs was correlated with worse distant relapse-free interval (HR=1.55; p=0.0172) and breast cancer-specific survival (HR=2.10; p&amp;lt;0.001). Conclusions: Standard clinico-pathological features were similar in pure and non-pure IMPC. Despite high proportion of grade 3 differentiation and lymph node involvement, we observed a low rate of distant metastasis and within the pure IMPC (59% of patients), no distant relapses occurred. These findings could be explained by the high proportion of luminal-A like tumors in our cohort and need confirmation. Higher sTILs was associated with worse outcome in this IMPC cohort, confirming previously published observations. Citation Format: Kevin Punie, Frederik Deman, Annouschka Laenen, Timothy Faes, Hans Wildiers, Ann Smeets, Ines Nevelsteen, Chantal Van Ongeval, Adinda Baten, Melissa Christiaens, Eva Oldenburger, Hilde Janssen, Caroline Weltens, Tatjana Geukens, Nynke Willers, Jan Ardui, Hava Izci, Laurence Slembrouck, Patrick Neven, Christine Desmedt, Giuseppe Floris. Clinical and pathological features of invasive micropapillary carcinoma of the breast and correlation with prognosis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-08-31.

Invasive micropapillary carcinoma of gallbladder: a clinicopathologic study

Objective: To study the clinicopathologic features of invasive micropapillary carcinoma (IMPC) of the gallbladder. Methods: Among 160 resected cases of gallbladder adenocarcinomas, the clinical and histological features of gallbladder adenocarcinomas with invasive micropapillary components (IMPC≥5%) were studied. Results: The detection rate of IPMC among gallbladder adenocarcinomas was 19.4% (31/160). Among these 31 cases, the patients' age ranged from 42 to 84 years (mean 64.8 years). The male-to-female ratio was 1∶4.Histologically, 19 cases were characterized by small papillary tufts lacking central fibrovascular cores, lying freely within the clefts of fibrous tissue, resembling IMPC of the breast; in five cases, the micropapillary tufts floated within cystic spaces lined by tumor cells, resembling IMPC of the lung; in four cases, slender, delicate filiform processes on the tumor surface with classic IMPC in the depth of gallbladder was observed; and in three cases mixed features were seen. Small cluster invasion (SCI) was seen adjacent to the IMPC. The lymph node metastatic rate, the lymphovascular invasion rate, and the SCI detection rate were significantly higher in the IMPC group (P=0.000). The IMPC detection rate was related to poorer histological differentiation and increased T stage (P=0.012, C=0.67; P=0.011, C=0.68). The two-year survival rate of IMPC (4/18) was significantly lower than usual gallbladder carcinoma (54.8%, 23/42). Conclusions: Compared to conventional adenocarcinoma of the gallbladder, IMPC has a more advanced tumor status and is prone to lymphovascular invasion and lymph node metastasis, which thus leads to short-term survival. Moreover, SCI may play an important role in the invasion of the IMPC of the gallbladder.

乳腺原発 invasive micropapillary carcinoma の細胞学的検討

乳腺原発 invasive micropapillary carcinoma の細胞学的検討

Clinicopathological features of invasive micropapillary carcinoma of the breast.

The aim of the present study was to evaluate the clinical and immunohistopathological findings of invasive micropapillary carcinoma (IMPC) of the breast. In total, 25 patients were included in the present study, all of whom were diagnosed with IMPC. The mammography and ultrasound scanning (US) findings were analysed retrospectively according to the American College of Radiology Breast Imaging Reporting and Data System lexicon. Surgical specimens obtained from the patients were microscopically reviewed in consensus by two pathologists with a specialisation in breast pathology. All the patients presented with palpable lumps in the breast, a high-density irregular mass associated with microcalcifications revealed by mammography and an irregular hypoechoic mass with a spiculated margin revealed by US. Axillary lymph node metastases were identified in 80% of the patients. Immunohistochemical studies revealed the lesions to be highly positive for the oestrogen receptor (ER) and c-erbB-2 (88% and 84%, respectively). Although no significant imaging characteristics were found to distinguish IMPC from typical invasive ductal carcinoma, IMPC resulted in nodal metastases and was highly positive for ER and c-erbB-2. This clinical significance indicates the significance of this entity being recognised by pathologists and surgeons.

Invasive Micropapillary Carcinoma of the Breast: Mammographic, Sonographic and MR Imaging Findings

Purpose : We performed this study to investigate the characteristic imaging and clinicopathologic features of invasive micropapillary carcinoma of the breast. Materials and Methods: Among the 47 women with surgically confirmed invasive micropapillary carcinoma between 2005 and 2009, 32 patients (mean age, 50 years; range, 37-69 years) had all preoperative mammography, ultrasound (US) and MR images. Two radiologists retrospectively assessed the imaging findings, clinical presentation and histological results of the patients. Results: On mammography, 29 of 32 patients had suspicious findings. Among them, a mass (or focal asymmetry) with calcifications was the most common findings (15/32, 65%). The calcifications were noted in 20 patients (63%) and the shape of calcifications was frequently amorphous or punctate (n = 12, 60%). On US and MR imaging, all lesions had suspicious findings. The most common US findings were single (n = 20) or multiple (n = 10) irregular hypoechoic mass (es). The mass was frequently hypoechoic (n = 29, 97%). On MR imaging, the type of lesions was a mass or masses in 23 (72%), a mass combined with non-mass in six patients, and non-mass lesions in three patients. Histologically, axillary lymph nodes metastasis were very common (25/32, 78%). Asymptomatic clinical presentation was not usual (9/32, 28%). Conclusion: The imaging features of invasive micropapillary carcinomas strongly suggest malignancy. Microcalcifications on mammography, marked hypoechogenicity on US and an irregular mass, often combined with non-mass on MR are common. Axillary lymph node metastasis is commonly associated. Index words : Breast∙Carcinoma∙Invasive micropapillary carcinoma∙MR imaging∙Sonography

Imaging Findings of Invasive Micropapillary Carcinoma of the Breast

PurposeThe purpose of this study is to evaluate imaging and histopathologic findings including the immunohistochemical characteristics of invasive micropapillary carcinoma (IMPC) of the breast.MethodsTwenty-nine patients diagnosed with IMPC were included in the present study. Mammographic, sonographic, and magnetic resonance imaging (MRI) findings were analyzed retrospectively according to the American College of Radiology Breast Imaging Reporting and Data System lexicon. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) findings were also evaluated. Microscopic slides of surgical specimens were reviewed in consensus by two pathologists with a specialty in breast pathology.ResultsMost IMPCs presented as a high density irregular mass with a non-circumscribed margin associated with microcalcifications on mammography, as an irregular hypoechoic mass with a spiculated margin on ultrasound, and as irregular spiculated masses with washout patterns on MRI. PET-CT showed a high maximum standardized uptake value (SUVmax) (mean, 11.2). Axillary nodal metastases were identified in 65.5% of the patients. Immunohistochemical studies showed high positivities for estrogen receptor and c-erbB-2 (93.1% and 51.7µ, respectively).ConclusionEven though the imaging characteristics of IMPCs are not distinguishable from typical invasive ductal carcinomas, this tumor type frequently results in nodal metastases and high positivities for both estrogen receptor and c-erbB-2. The high SUVmax value that is apparent on PET-CT might be helpful in the diagnosis of IMPC.

Gastric carcinoma with invasive micropapillary pattern and its association with lymph node metastasis

This study aimed to characterize the clinicopathological features of invasive micropapillary carcinoma (IMPC) of the stomach. Seventeen cases of gastric IMPC were identified from histological reviews of 1178 consecutive cases. IMPC components occupied 10-90% of the entire tumours. Fifteen tumours showed invasion into the muscularis propria or deeper, whereas two tumours were limited to the submucosa. All 17 cases were associated with tubular or papillary adenocarcinoma. Lymphatic and venous invasion were identified more frequently in cases with IMPC components than in those without (P = 0.0023 and P = 0.0009, respectively). Nodal metastases were identified in 14 of 17 (82%) cases with IMPC components, whereas they were detected in 540 of 1161 (47%) cases with no IMPC components (P = 0.0053). Multivariate analysis demonstrated that the presence of IMPC was an independent predictor of nodal metastasis. Conservative treatments, such as endoscopic resection, should not be used for gastric carcinoma with IMPC components, as these cases are associated with a high propensity for lymphovascular invasion and nodal metastasis.

The clinicopathological significance of CD44 +/CD24 −/low and CD24 + tumor cells in invasive micropapillary carcinoma of the breast

Breast cancer cells with a CD44 +/CD24 −/low phenotype have been suggested to have tumor-initiating properties. It is unclear whether their presence correlates with clinicopathological features of invasive micropapillary carcinoma (IMPC) of the breast, an unusual subtype of breast cancer with a high incidence of lymph node metastasis and poor prognosis. CD44 and CD24 expression was determined by double-staining immunohistochemistry in 103 cases of IMPC and in 94 cases of invasive ductal carcinoma (IDC). The prevalence of CD44 +/CD24 −/low tumor cells was higher in IMPC than in invasive ductal carcinoma IDC ( P = 0.018). The CD44 +/CD24 −/low tumor cells were also detected in adjacent stroma surrounding the micropapillary structure in 53.4% (55/103) of IMPC, but only in 7.4% (7/94) of stroma of IDC. These tumor cells in stroma of IMPC were positive for vimentin and α-smooth muscle actin, and negative for E-cadherin. The CD44 +/CD24 −/low tumor cells in the micropapillary structure of IMPC were associated with those in stroma ( P = 0.000). Moreover, they were both associated with lymphovascular invasion and extranodal extension, respectively ( P < 0.05). The proportion of CD24 + tumor cells was also higher in IMPC than in IDC ( P = 0.035), and the CD24 + tumor cells were associated with lymph node metastasis in IMPC ( P = 0.010). The results suggest that the increased proportion of CD44 +/CD24 −/low tumor cells and CD24 + tumor cells and the epithelial mesenchymal transition may play an important role in aggressiveness and high metastatic risk of breast IMPC.

391 Characteristics of invasive micropapillary carcinoma of the breast: Is it related to the triple negative breast cancer?

Invasive micropapillary carcinoma (IMPC) of the breast and triple negative breast cancer (TNBC) are both aggressive subtypes, but little information is available on their comparison.Retrospective analysis of 95 IMPC and 200 TNBC-IDC (invasive ductal carcinoma) was conducted to compare the clinicopathologic characteristics and survivals.For IMPC, pN was the independent prognostic factor of local-regional recurrence free survival (LRRFS) (P = 0.045) and metastasis free survival (MFS) (P = 0.048), but not of overall survival (OS) (P = 0.165). For TNBC, pT and lymphovascular invasion (LVI) were both independent prognostic factors of MFS (pT: P = 0.006, LVI: P = 0.010) and OS (pT: P = 0.006, LVI: P = 0.001), but not for LRRFS (pT: P = 0.060, LVI: P = 0.503). IMPC exhibited more aggressive features than TNBC, including larger tumor size, a greater proportion of nodal involvement, and an increased incidence of LVI. After a median follow-up duration of 61 months, 5y-LRRFS rate was lower in IMPC than in TNBC, in entire cohort (71.4 ± 4.8% vs. 89.8 ± 2.2%, P < 0.001) and in node positive cases (64.2 ± 5.9% vs. 81.7 ± 4.4%, P = 0.048). A tendency of lower 5y-MFS rate was observed in TNBC compared with in IMPC, in node positive cases (63.8 ± 5.5% vs. 74.8 ± 5.5%, P = 0.053) and in node negative cases (80.1 ± 3.6% vs. 96.2 ± 3.8%, P = 0.052), but it did not reach significance. 5y-OS was similar between IMPC and TNBC (81.9 ± 4.7% vs. 79.8 ± 3.1%, P = 0.475).IMPC is featured with high rate of lymph node involvement which is strongly associated with high rate of LRR. TNBC is featured with high rate of early distant metastasis without increase of nodal metastases. The survival is still relatively poor even in node negative cases.

Characteristics of Invasive Micropapillary Carcinoma of the Breast: In Comparison with Invasive Ductal Carcinoma

Purpose: Invasive micropapillary carcinoma (IMPC) of the breast is a rare and associated with high incidence of lymph node metastasis and poor outcome. The aims of this study were to provide a comprehensive analysis of clinicopathologic and immunohistochemical characteristics of IMPC and to elucidate the differences between IMPC and invasive ductal carcinoma (IDC). Methods: Sixty-one patients of IMPC were identified by retrospective review of database from January 2004 to December 2008. 221 patients were randomly selected among the IDC patients who received operation during the same period. Two groups were compared with uni- and multivariate analysis. Results: We observed significant differences in mean number of metastatic lymph nodes (6.1 vs. 1.9, p= 0.001), positivity of lymph node (70.5% vs. 45.2%, p<0.001), and presence of lymphatic vessel invasion (75.4% vs. 34.8%, p <0.001) between IMPC and IDC patients. Although it has been known that triple negative breast cancer (TNBC) have lymphotropic tendency in their early T stage, 11.8% (26/221) of IDC and 3.3% (2/61) of IMPC patients were TNBC in this study (p=0.050). In multivariate analysis, IMPC histology showed no correlation with disease-free survival (DFS) and the lymphatic vessel invasion was a significant predictor of DFS. Conclusion: The results of this study confirm that IMPC is unique subtype of breast cancer that is commonly accompanied by axillary lymph node metastasis and shows poor outcome, although it rarely presents the pattern of TNBC. Lymphatic vessel invasion rather than histology of IMPC seems to be more closely related to DFS.

Invasive Micropapillary Carcinoma of the Breast: Mammographic, Sonographic, and MRI Features

The purpose of this study was to describe the clinical, imaging, and histopathologic findings of invasive micropapillary carcinoma of the breast. The imaging characteristics of invasive micropapillary carcinoma are highly suggestive of malignancy. The lesion is a high-density irregular mass with indistinct margins associated with microcalcifications on mammograms; a solid irregular hypoechoic mass with indistinct margins and frequent axillary nodal involvement on sonograms; and a multifocal mass on MR images. This tumor may necessitate aggressive management.

Pathologic and clinical features of invasive micropapillary carcinoma of breast

乳腺浸润性微乳头状癌(IMPC)因其具有独特的组织形态特点和高度的淋巴管侵犯、淋巴结转移及预后较差的特点,在2003年10月出版的WHO乳腺和女性生殖系肿瘤的病理学与遗传学分类中,作为一种新的肿瘤类型被单列出来.本研究旨在了解乳腺IMPC的临床病理特点。

Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast

To determine the pathognomonic diagnostic cytological features of invasive micropapillary carcinoma of the breast which is a poor prognostic subtype of infiltrating ductal carcinoma. A series of 20 histologically proven tumours were reviewed retrospectively to evaluate the various cytological features, including tumour morules, isolated malignant cells, staghorn epithelial structures, mucinous background and apocrine metaplasia. Tumour morules formation and isolated malignant cells were the two most reliable and constant cytological features, being present in 75% (15/20 cases) of cases. Staghorn epithelial structures were present in 35% (7 cases). Mucinous background (2 cases, 10%) and apocrine metaplasia (4 cases, 20%) of the tumour cells were seen in a few cases only and did not appear very helpful. Tumour morules formation, isolated malignant cells and staghorn epithelial structures are the most reliable cytological features, and the presence of these should raise suspicion of invasive micropapillary carcinoma.

Imaging and the Clinical-Pathologic Features of Invasive Micropapillary Carcinoma of the Breast

Purpose: The purpose of this study was to describe the mammographic and sonographic appearances and the clinical-pathologic features of invasive micropapillary carcinoma. Materials and Methods: Between December 1999 and March 2005, among the 3,109 patients who underwent operation for breast cancer, 25 patients proved to have invasive micropaillary carcinoma. Among the 25 patients, we included 22 patients (mean age: 48, range: 26-77 years) who had undergone preoperative mammography and ultrasound. The mammographic and sonographic findings of the lesions were analyzed retrospectively. The pathologic findings were analyzed via the clinical records and pathology reports. Results: Patients manifested with a palpable mass (77%, 17/22), bloody nipple discharge (14%, 3/22) or incidental lesion on the screening mammography (9%, 2/22). On mammography, a mass with an irregular (86%, 12/14) shape and an indistinct (43%, 6/14) or spiculated (43%, 6/14) margin was the most common findings on mammography. On sonography, a hypoechoic (91%, 20/22) mass with irregular shape (73%, 16/22) and an indistinct (32%, 7/22) or microlobulated (32%, 7/22) margin was the most common finding. Pathologically, axillary lymph node metastasis was present in 73% (16/22) of the patients. Conclusion: Invasive micropapillary carcinoma appeared an irregular shaped mass with an indistinct margin mass or microcalcifications on mammography and/or sonography. The tumors were frequently associated with axillary lymph node metastasis.

3072: Sonographic characteristics of invasive micropapillary carcinoma of the breast

Objectives: The purpose of our study was to investigate the imaging features of invasive micropapillary carcinoma of the breast, which is recently described and have poorer prognosis, variant of infiltrating ductal carcinoma.

The reversed apical pattern of MUC1 expression is characteristics of invasive micropapillary carcinoma of the breast

Invasive micropapillary carcinoma (IMPC) of the breast is a special subtype of invasive ductal carcinoma (IDC), which is known to have a high potential to metastasize to the axillary lymph node. However, it is sometimes difficult to differentiate IMPC from conventional IDC showing an IMPC-like pattern due to artifact (pseudo-IMPC). In the present study, we investigated the usefulness of immunohistochemical expression of MUC1 for distinguishing IMPC from pseudo-IMPC, and analyzed several clinicopathological parameters of IMPC and pseudo-IMPC cases. Eighty cases showing IMPC or IMPC-like pattern were selected from our surgical files of 1,240 cases of IDC. We examined the expression of MUC1, D2-40 and CD34 by immunohistochemistry. Eighty cases were classified into 9 cases (0.7%) of pure-IMPC, 31 cases (2.5%) of mixed-IMPC, and 40 cases of pseudo-IMPC, according to the expression pattern of MUC1. In pure-IMPC cases, MUC1 expression was found at the reversed apical membrane of neoplastic cell clusters, while in pseudo-IMPC, MUC1 expression was present in the whole cytoplasmic membrane and/or cytoplasm. There were no significant differences among the three groups in patient age, tumor size and nuclear grade of neoplastic cells. However, lymphatic invasion and lymph node metastasis in the pure-IMPC or mixed-IMPC cases were higher than those in pseudo-IMPC cases with statistically significant values. Pure-IMPC has a higher recurrence rate and lower overall survival compared to pseudo-IMPC [P = 0.0165(DFS) P = 0.025(OS)]. This study demonstrated that immunohistochemistry of MUC1 is useful for the diagnosis of IMPC. The pure-IMPC cases had higher incidences of lymphatic invasion and lymph node metastasis, and also showed a poorer prognosis.

Clinical and pathologic features of invasive micropapillary carcinoma

Invasive micropapillary carcinoma(IMC)of the breast is a rare subtype of breast carcinoma that has an extremely high incidence of lymph node metastases and poor clinical outcome. This histological subtype of breast carcinoma has remained unclear due to the rarity of cases. Many questions exist on the clinicopathological significance of this subtype, especially regarding prognosis. We reviewed all 671 cases of primary breast carcinoma that were surgically resected at our institute between 1990 and 2004. Of these, 27 cases of invasive ductal carcinoma of the breast with a pure or partial micropapillary component were reported. The cases were analyzed using various parameters, including age at presentation, tumor size, tumor grade, presence of lymphatic invasion, and axially lymph node status. The patients' age at presentation ranged from 31 to 74 years (mean 52.4 years). Tumor size ranged from 0.7 to 10 cm (mean 4 cm). 88.9% (24 of 27) of the cases had lymphatic invasion. Of cases who underwent with axillary dissection, 66.6% (18 of 27) had positive lymph nodes. Clinical follow up data were available for 17 cases with IMC for 1 to 72 months. Among these, 10 patients died from breast carcinoma within 5 years. While our series is too small to make conclusions about the behavior of IMC, the difference in 6-year survival rate between the patients with IMC and those with breast carcinoma in general was statistically significant. Recognition of this distinctive and aggressive variant of infiltrating carcinoma is important because of its poor prognosis and high incidence of lymph node metastases.

乳腺Ｉｎｖａｓｉｖｅ ｍｉｃｒｏｐａｐｉｌｌａｒｙ ｃａｒｃｉｎｏｍａの細胞学的特徴

目的:今回われわれは, 乳腺invasive micropapillary carcinoma (以下IMPC) の細胞学的特徴を見出すことを目的とし, 細胞像を検討した. その細胞像から新たな亜分類を提唱したい.対象および方法:織学的にIMPCと診断された10例を用いて, 共焦点レーザー走査顕微鏡による立体構築像および超微細形態学的所見, 免疫組織学的所見について検討し, 細胞像との比較検討を試みた.結果:IMPCの細胞像は, 組織像を反映した立体的細胞集塊 (three-dimentional cell cluster;3DCC) の出現であると考えられた. また, これらの3DCCはその形状から腔形成型IMPC (lumen-forming type IMPC;L型) と充実型IMPC (solid type IMPC;S型) の2つに亜分類された. 10例中, 4例がL型で6例がS型であった. 両者の細胞像には若干の差異がみられた. すなわち, S型はL型に比して,(1) 細胞・核ともに大型で細胞異型が強い傾向がある,(2) 散在性細胞が多い,(3) 3DCC最外層の核配列は規則性を認めない症例が多く, さらに集塊辺縁の “けばだち状” 所見をみる3DCCの出現頻度が低く, IMPCのなかでもS型は予後が悪い可能性が示唆された. また, MIB-1 indexではS型に増殖能を示す細胞が高率に認められた.結語:IMPCの細胞学的特徴は, 結合性の高い3DCCの出現であった. 今回のわれわれの検討からIMPCは, L型とS型に細分類されることを明らかにした. L型は “けばだち状” の所見を呈する3DCCから構成される典型像を示すのに対し, S型では3DCCの出現頻度も少なく, 散在性細胞が目立つ症例の存在も認めた. したがって, 細胞診でのIMPCの診断はL型のほかに, S型の存在も考慮する必要があると考えられた.