Fine-needle aspiration cytology findings of an uncommon micropapillary variant of pure mucinous carcinoma of the breast: review of patients over an 8-year period

On Ultrasonographic Features of Mucinous Carcinoma with Micropapillary Pattern

Objective

To describe the sonographic features of pure mucinous carcinoma with micropapillary pattern (MUMPC) and compare with different pathological type of mucinous breast carcinoma.

Methods

Subjects were retrospectively reviewed at Suzhou Municipal Hospital from January 2015 to June 2019. Sonographic features of 49 cases (9 MUMPC, 19cPMBC, and 21 MMBC) pathologically confirmed MBC were recorded according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon. The differences in sonographic features among different type of mucinous breast carcinoma were discussed, including clinical features and sonographic features, shape, lesion boundary, peripheral hyperechoic ring, echo pattern, posterior acoustic feature, thickness peripheral hyperechoic area, and blood flow.

Results

All MUMPC had no lymph node metastasis (88.9%, 8/9), and most of the MUMPC showed no thickness peripheral hyperechoic area (88.9%, 8/9) and blood flow (55.6%, 5/9) within the tumor. Furthermore, MUMPC had mixed cystic and solid components (33.3%, 3/9) and solid echoic (66.7%, 6/9) structures, with regular shape (66.7%, 6/9) and peripheral hyperechoic ring (66.7%, 6/9). Seven cases of the MUMPC showed circumscribed margin (77.8%, 7/9), and there was significant difference among the three groups (p < 0.05). In addition, there were 7 cases (77.8%, 7/9) of MUMPC tumor ≤2cm, which was significantly different from cPMBC (26.3%, 5/19) and MMBC (28.6%, 6/21) (p < 0.05). There was no significant difference in ultrasonographic features of MBC with different sizes when stratified by tumor size (p > 0.05).

Conclusion

Most of the MUMPC showed a circumscribed margin, peripheral hyperechoic ring, and without lymph node metastasis and thickness peripheral hyperechoic area. However, it is challenging to distinguish MUMPC from PMBC and MMBC on ultrasound. Future research should focus on developing novel analysis methods for ultrasound imaging, conducting studies with larger sample sizes and diverse population groups.

Cytology of micropapillary mucinous carcinoma: A case report of a clinically and genetically distinct breast carcinoma variant

Micropapillary mucinous carcinoma (MPMC) is an uncommon histopathological variant of breast cancer accounting for approximately one-fifth of all mucinous breast carcinomas. In contrast to pure mucinous carcinoma, MPMC tends to affect younger women and is associated with decreased progression-free survival, higher nuclear grade, lymphovascular invasion, lymph node metastasis, and positive HER2 status. Typically MPMC histology shows micropapillary architecture with "hobnailing" of cells and reverse polarity. Very few publications document the cytomorphological findings of MPMC. We report a case of MPMC that was suspected in fine needle aspiration cytology (FNAC) and confirmed at histopathology.

The Spectrum of Mucinous Lesions of the Breast

CONTEXT.—

Mucinous lesions of the breast encompass many entities ranging from benign to malignant and nonneoplastic to neoplastic. Lesions discussed under this category are mucocele-like lesion, mucinous carcinoma, mucinous micropapillary carcinoma, solid papillary carcinoma, mucinous cystadenocarcinoma, mucoepidermoid carcinoma, invasive lobular carcinoma with extracellular mucin, mucinous ductal carcinoma in situ, and metastasis.

OBJECTIVE.—

To review clinical, pathologic, and molecular features of mucinous lesions of the breast, their differential diagnoses, and challenging features on core needle biopsies.

DATA SOURCES.—

The existing scientific and clinical literature as of December 2021.

CONCLUSIONS.—

The category of mucinous lesions of the breast is vast and the differential diagnosis can be challenging, especially on core needle biopsies. In all cases, clinical, radiologic, and pathologic correlation is necessary to reach a comprehensive diagnosis. Given that the prognosis and management of each entity is different, being aware of these entities and their nuances is critical for a pathologist to guide accurate management.

Sonographic Features of Pure Mucinous Brelast Carcinoma With Micropapillary Pattern

Objective

Previous studies have mostly discussed the clinical manifestations and prognosis of mucinous breast carcinoma with a micropapillary pattern. The purposes of this study were to investigate the sonographic features of pure mucinous breast carcinoma with micropapillary pattern (MUMPC) and to identify the role of ultrasound in the differential diagnosis between MUMPC and conventional pure mucinous breast carcinoma (cPMBC).

Materials and Methods

We obtained written informed consent from all patients, and the Ethics Committee of West China Hospital approved this retrospective study. The study was conducted between May and August 2020. We enrolled 133 patients with 133 breast lesions confirmed as mucinous breast carcinoma (MBC) histopathologically between January 2014 and January 2020.We retrospectively assessed sonographic features (margin, shape, internal echogenicity, calcification, posterior acoustic feature, invasive growth, blood flow grade, and rate of missed diagnosis) and clinical characteristics (age, tumor size, tumor texture, initial symptom, and lymph node metastasis). Bivariable analyses were performed using SPSS version 19.0.

Results

The 133 lesions included 11 MUMPCs, 65 cPMBCs, and 57 mixed MBCs (MMBCs). There were significant differences in margin, shape, calcification, posterior acoustic feature, invasive growth, rate of missed diagnosis, average tumor size, and lymph node metastasis among the three groups (p < 0.05). The subsequent pairwise comparisons showed that there were significant differences in lymph node metastasis, margin, and invasive growth between MUMPC and cPMBC (p < 0.05). In patients aged >45 years, there was a significant difference in tumor size among the three groups (p = 0.045), and paired comparison showed that the average tumor size in the cPMBC group was larger than that in the MMBC group (p = 0.014).

Conclusion

MUMPC showed a non-circumscribed margin and invasive growth more frequently than cPMBC did. Lymphatic metastasis was more likely to occur in MUMPC than cPMBC. Ultrasound is helpful to distinguish MUMPC from cPMBC.

Histological type and typing of breast carcinomas and the WHO classification changes over time

The World Health Organization’s new classification of breast tumors has just been published. This review aims to examine the morphological categorization of breast carcinomas which is still principally based on histological features and follows the traditions of histological typing. It gives a subjective and critical view on the WHO classifications and their changes over time, and describes the changes related to some of the most common or challenging breast carcinomas: in situ carcinomas, invasive breast carcinomas of no special type, lobular, cribriform, tubular, mucinous, papillary, metaplastic carcinomas and carcinomas with medullary pattern and those with apocrine differentiation are discussed in more details. Although the 5^th edition of the classification is not perfect, it has advantages which are mentioned along with problematic issues of classifications.

Mucinous carcinoma with micropapillary features is morphologically, clinically and genetically distinct from pure mucinous carcinoma of breast

Micropapillary features are seen in pure mucinous carcinoma of breast (PMC), which is termed mucinous carcinoma with micropapillary features (MPMC). However, whether MPMC can be identified as a morphologically, clinically or genetically distinct entity from PMC remains controversial. In this study, a retrospective review of 161 cases of breast mucinous carcinoma was conducted to assess the clinicopathologic features, prognostic implications, and genomic alterations of MPMC and PMC. MPMCs were identified in 32% of mucinous carcinomas showing an excellent interobserver agreement (ICC = 0.922). MPMCs occurred at a younger age and exhibited higher nuclear grade, more frequent lymph nodal metastasis, lymphovascular invasion, and HER2 amplification compared with PMCs. Survival analyses revealed that MPMCs show decreased progression-free survival compared with PMCs in both unmatched and matched cohorts. A similar outcome of distant disease-free survival was observed only in the unmatched cohort. However, no statistical difference in recurrence score was observed between MPMC and PMC using a 21-gene assay. Notably, both MPMCs and PMCs displayed low mutation burden, common mutations affecting TTN, GATA3, SF3B1, TP53, recurrent 6q14.1-q27 losses, and 8p11.21-q24.3 gains. GATA3, TP53, and SF3B1 were recurrently mutated in MPMCs, while PIK3CA mutations were exclusively detected in PMCs. Moreover, MPMCs harbored 17q and 20q gains as well as 17p losses, while PMCs displayed gains at 6p. PI3K-Akt, mTOR, ErbB, and focal adhesion pathways were more frequently deregulated in MPMCs than in PMCs, which may responsible for the aggressive tumor behavior of MPMCs. Our findings suggest that MPMC is morphologically, clinically, and genetically distinct from PMC.

A review of mucinous lesions of the breast

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocele-like lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The finding of free-floating or stromal mucin accumulations is a diagnostic challenge of which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between benign and malignant mucin-producing lesions, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with associated with mucinous, myxoid, or matrix material.

Pure Mucinous Breast Carcinoma with Micropapillary Pattern (MUMPC): A Case Report

Pure mucinous breast carcinoma with micropapillary pattern (MUMPC) was proposed as a new histopathological variant of pure mucinous carcinoma (PMC) with tumor cells forming a micropapillary architecture. The Classification of Tumours of the Breast by the World Health Organization, however, does not differentiate MUMPC as a distinct subtype. There is currently no consensus whether tumors that exhibit these features are classified as PMC or invasive micropapillary carcinoma (IMPC) with associated mucin production. A 45-year-old woman was examined for a tumor in her left breast. Upon physical examination, an elastic hard mass of around 5 cm along with accompanying skin flare and ulceration was palpated in the upper outer quadrant of the left breast. Mammary ultrasonography revealed a clearly marginated hypoechoic tumor of 55.0 × 46.9 × 37.0 mm in size in the upper outer quadrant of the left breast. A vacuum-assisted biopsy (VAB) was performed in the same site and histopathological diagnosis of PMC was made. Contrast-enhanced magnetic resonance imaging (MRI) showed a T1W1 low-intensity signal and a T2W1 high-intensity signal at the primary focus, ring enhancement of the tumor margin, and stranding enhancement inside the tumor. A preoperative diagnosis of left breast cancer (PMC), cT4bN1M0, stage IIIB, luminal B-like was made. We performed a simple mastectomy with axillary lymph node dissection. A 55.0 × 48.1 × 37.1 mm tumor with the gelatinous cut surface was excised. Histopathological examination of the excised specimen revealed mucin lake formation in the tumor containing clusters of atypical cells. The atypical cells showed swollen, irregular nuclei and a papillary growth pattern that lead to the diagnosis of MUMPC.

The sonographic findings of micropapillary pattern in pure mucinous carcinoma of the breast

BACKGROUND

The aim of this study was to describe the sonographic features of pure mucinous carcinoma with micropapillary pattern (MUMPC) and compare them with conventional pure mucinous breast carcinoma without micropapillary architecture (cPMBC) and mixed mucinous breast carcinoma (MMBC).

METHODS

Eighty-eight patients (17 MUMPCs, 43 cPMBCs, and 28 MMBCs) were included in the study. Sonographic features according to the Breast Imaging Reporting and Data System (BI-RADS) lexicon for ultrasound (US) were recorded and analyzed for each patient. The age, sonographic lesion size, menstrual status, mass location, palpation, tenderness, and axillary lymph node metastasis (LNM) were also analyzed.

RESULTS

Most of the MUMPCs showed an irregular shape (82.4%, 14/17), a parallel orientation (94.1%, 16/17), a non-circumscribed margin (88.2%, 15/17), and distal acoustic enhancement (88.2%, 15/17). Furthermore, MUMPC had mixed cystic and solid components (35.3%, 6/17) and hypoechoic (29.4%, 5/17) and isoechoic (35.3%, 6/17) structures, with calcification (29.4%, 5/17) and blood flow (41.2%, 7/17) within the tumor. The differences in sonographic features were not found between the MUMPC and cPMBC and between the MUMPC and MMBC. Moreover, there was no significant difference between the three groups based on age, menstrual status, mass location, palpation, and tenderness (p > 0.05). Similar axillary LNMs were observed between MUMPC and cPMBC (p > 0.05), but both MUMPC and cPMBC were statistically different from MMBC (p < 0.05), so as the lesion size.

CONCLUSIONS

At this particular stage, it is challenging to distinguish MUMPC from cPMBC and MMBC on ultrasound according to the BI-RADS-US lexicon.

Prognosis of subtypes of the mucinous breast carcinoma in Chinese women: a population-based study of 32-year experience (1983-2014)

Purpose

The heterogeneous nature of the mucinous breast cancer (MBC), with its pure (PMBC) and mixed subtypes (MMBC), calls for precise prognosis assessment.

Methods

We analyzed 197 consecutive MBC patients, including 117 PMBC and 80 MMBC, who were treated from 1983 to 2014. The clinicopathological features, treatment choice, disease-free survival (DFS) and overall survival (OS) were compared among PMBC, MMBC and MMBC subgroups. Prognostic factors of PMBC and MMBC were identified.

Results

Compared to PMBC, MMBC had more lymph node metastasis (p = 0.043), Her2 positivity (p = 0.036), high Ki-67 index (defined as>20%, p = 0.026) and anti-Her2 targeted therapy (p = 0.016). The 5-year DFS of PMBC and MMBC were 90.4% and 86.2%, whereas the 5-year OS were 99.0% and 98.7%. No significant difference was found in DFS or OS among all MBC subtypes. High Ki-67 (p = 0.020) appeared as DFS factor in PMBC, while anti-Her2 targeted therapy (p = 0.047) as the DFS predictors in MMBC.

Conclusion

MMBC manifested similar 5-year survival to PMBC in Chinese woman, suggesting that intra-tumoral heterogeneity might not interfere with MBC short-term prognosis.

Micropapillary variant of mucinous breast carcinoma: A distinct subtype

Invasive micropapillary carcinoma of the breast is a subtype with high malignant potential characterized by lymphovascular invasion (LVI) and a predilection for axillary lymph node (AXLN) metastases. In contrast, pure mucinous breast carcinoma (MBC) is relatively indolent with low metastatic potential. Recent studies have described a histologic variant of breast cancer that displays combined mucinous and micropapillary patterns, ie, micropapillary variant of mucinous carcinoma (MpVMBC). This underrecognized variant is, as yet, incompletely characterized clinicopathologically. Extant reports suggest a more aggressive lesion than pure MBC with greater propensity for both LVI and AXLN metastases. Here we present our institution's experience with MpVMBCs including clinicopathologic and immunohistochemical (IHC) analyses. Greater awareness and recognition of this variant could positively contribute to patient care by (1) avoiding underestimation of malignant potential for individuals whose tumors may have been diagnosed as simply "MBC, not otherwise specified", and (2) recommending a postsurgical adjuvant approach emphasizing the hormone receptor targets, even perhaps in younger women presenting with AXLN positive disease.

Cadherin-mediated cell-cell interactions in normal and cancer cells

Adherens junctions (AJs) are molecular complexes that mediate cell-cell adhesive interactions and play pivotal roles in maintenance of tissue organization in adult organisms and at various stages of development. AJs consist of cadherin adhesion receptors, providing homophilic ligation with cadherins on adjacent cells, and members of the catenin protein family: p120, β- and α-catenin. α-catenin's linkage with the actin cytoskeleton defines the linear or punctate organization of AJs in different cell types. Myosin II-dependent tension drives vinculin recruitment by α-catenin and stabilizes the linkage of the cadherin/catenin complex to F-actin. Neoplastic transformation leads to prominent changes in the organization, regulation and stability of AJs. Epithelial-mesenchymal transition (EMT) whereby epithelial cells lose stable cell-cell adhesion, and reorganize their cytoskeleton to acquire migratory activity, plays the central role in cancer cell invasion and metastasis. Recent data demonstrated that a partial EMT resulting in a hybrid epithelial/mesenchymal phenotype with retention of E-cadherin is essential for cancer cell dissemination. E-cadherin and E-cadherin-based AJs are required for collective invasion and migration, survival in circulation, and metastatic outgrowth.

Prognostic Significance of a Micropapillary Pattern in Pure Mucinous Carcinoma of the Breast: Comparative Analysis with Micropapillary Carcinoma

BACKGROUND

Mucinous carcinoma of the breast is an indolent tumors with a favorable prognosis; however, micropapillary features tend to lead to aggressive behavior. Thus, mucinous carcinoma and micropapillary carcinoma exhibit contrasting biologic behaviors. Here, we review invasive mucinous carcinoma with a focus on micropapillary features and correlations with clinicopathological factors.

METHODS

A total of 64 patients with invasive breast cancer with mucinous or micropapillary features were enrolled in the study. Of 36 pure mucinous carcinomas, 17 (47.2%) had micropapillary features and were termed mucinous carcinoma with micropapillary features (MUMPC), and 19 (52.8%) had no micropapillary features and were termed mucinous carcinoma without micropapillary features. MUMPC were compared with 15 invasive micropapillary carcinomas (IMPC) and 13 invasive ductal and micropapillary carcinomas (IDMPC).

RESULTS

The clinicopathological factors of pure mucinous carcinoma and MUMPC were not significantly different. In contrast to IMPC and IDMPC, MUMPC had a low nuclear grade, lower mitotic rate, higher expression of hormone receptors, negative human epidermal growth factor receptor 2 (HER2) status, lower Ki-67 proliferating index, and less frequent lymph node metastasis (p < .05). According to univariate analyses, progesterone receptor, HER2, T-stage, and lymph node metastasis were significant risk factors for overall survival; however, only T-stage remained significant in a multivariate analysis (p < .05).

CONCLUSIONS

In contrast to IMPC and IDMPC, the micropapillary pattern in mucinous carcinoma does not contribute to aggressive behavior. However, further analysis of a larger series of patients is required to clarify the prognostic significance of micropapillary patterns in mucinous carcinoma of the breast.

Invasive Micropapillary Carcinoma of the Breast: An Update

CONTEXT

-Invasive micropapillary carcinoma (IMPC) is a distinct variant of mammary carcinoma in which tumor cells are arranged in morulelike clusters devoid of fibrovascular cores and situated within empty stromal spaces. Identification of IMPC can be achieved by the assessment of morphologic features in conjunction with the characteristic "inside-out" staining pattern of epithelial membrane antigen and sialyl Lewis X highlighted by immunohistochemical analysis. Although recognizing micropapillary architecture is often not challenging, the criteria for distinguishing between mixed and pure IMPC remain imprecise. Some mucin-producing carcinomas can also have micropapillary histology, but there is no consensus on whether these tumors are variants of IMPC or mucinous carcinomas. The molecular genetic studies demonstrate that IMPCs have distinct molecular genetic profiles, supporting the theory that they constitute distinct pathologic entities. However, genomic analyses have not identified any specific genomic aberration that may explain the distinctive morphology and clinical behavior of IMPC.

OBJECTIVE

-To provide an overview on the current concepts in the diagnosis and pathogenesis of IMPC of the breast, incorporating recent molecular genetic advances and prognosis-based reclassification.

DATA SOURCES

-PubMed search and the cited references were reviewed.

CONCLUSIONS

-The recent evolution of prognosis-based reclassification and molecular genetic advances has enhanced our knowledge of the pathogenesis of IMPC of the breast. Additional studies might reveal consistent molecular alterations that underlie the formation of the inside-out growth pattern, and they might elucidate the molecular mechanisms responsible for the unfavorable clinical behavior of IMPC.

Invasive micropapillary mucinous carcinoma of the breast is associated with poor prognosis

Invasive micropapillary carcinoma of breast (IMpC) is a special type of breast cancer with frequent lymph node metastasis (LNM) and poor prognosis, while pure mucinous carcinoma of breast (PMC) is generally associated with infrequent LNM and better prognosis. A similar micropapillary epithelial growth pattern has been described in PMC that was named as invasive micropapillary mucinous carcinoma (IMpMC), but its prognostic significance is as yet not known. A retrospective review of 531 cases of PMC in 43,685 cases of breast cancer diagnosed over a 10-year period was conducted to assess the frequency of IMpMC and its prognostic implications. IMpMC was identified in 134 (25.2 %) of the 531 PMC cases. Compared to conventional PMC (cPMC), IMpMC was found more frequently in younger patients and in tumors with increased frequency of LNM and lymphovascular invasion, and higher HER2 expression. In stage-matched Kaplan-Meier analysis, patients with stage II-III IMpMC suffered a decreased overall survival and recurrence-free survival (RFS) than matched cPMC patients. Multivariate analysis confirmed the presence of IMpMC morphology was an independent unfavorable predictor for LNM and RFS of PMC. However, decreased LNM, lower nuclear grade, higher expression of ER and PR, less expression of HER2, and better prognosis were identified in IMpMC when compared with IMpC (n = 281). This is the first study to show the prognostic significance of IMpMC in a large cohort. IMpMC pursues a more aggressive clinical course than cPMC and should be managed differently; therefore, recognition of IMpMC and its accurate diagnosis are clinically important.

Mucinous micropapillary carcinoma of the breast: an aggressive counterpart to conventional pure mucinous tumors

Mucinous micropapillary carcinoma of the breast, also described as "pure mucinous carcinoma with micropapillary pattern," has recently come to attention as an unusual form of invasive breast cancer exhibiting dual mucinous and micropapillary differentiation. Despite increasing awareness of this morphologic variant, its clinical significance has not yet been elucidated. Here, we present 15 additional examples of these rare tumors to highlight some important differences between mucinous micropapillary carcinoma of the breast and ordinary pure mucinous carcinomas. The key features of mucinous micropapillary carcinoma of the breast included (a) largely or entirely mucinous appearance (>90% mucinous morphology), (b) distinctive micropapillary arrangement of the neoplastic cells, (c) intermediate to high nuclear grade, (d) "hobnail" cells, and (e) frequent psammomatous calcifications. In contrast to ordinary pure mucinous carcinomas, 20% of mucinous micropapillary carcinomas of the breast were characterized by human epidermal growth factor receptor 2 positivity, and 23% were p53 positive. More than half of mucinous micropapillary carcinomas of the breast (60%) demonstrated lymphovascular invasion, sometimes extensive. Synchronous axillary lymph node metastases were detected in 33% of patients and, on 2 occasions, involved more than 10 nodes. With a median follow-up of 4.5 years, we identified 1 patient (7%) with chest wall recurrence of mucinous micropapillary carcinoma of the breast after mastectomy. We conclude that mucinous micropapillary carcinomas of the breast constitute a clinically aggressive subset of mucin-producing breast carcinomas characterized by an increased capacity for lymphatic invasion and regional lymph node metastasis, reflective of their dual phenotype. Recognition of the morphologic and biologic heterogeneity within breast cancer subtypes should allow for a more accurate classification of the individual tumors and better patient stratification for treatment.

Pancreatic cancer cells retain the epithelial-related phenotype and modify mitotic spindle microtubules after the administration of ukrain in vitro

The aim of this study is to characterize the phenotype of pancreatic ductal adenocarcinoma (PDAC) cells in relation to the expression of epithelial-to-mesenchymal transition (EMT) markers and determine whether ukrain, an anticancer drug based on the alkaloids extracted from greater celandine, modulates in vitro the malignant behavior of PDAC cells in order to extend our understanding of its therapeutic potential. Three cell lines (HPAF-II, HPAC, and PL45) were treated with ukrain (5, 10, and 20 μmol/l) for 48 h or left untreated (control). Cell proliferation was assessed by growth curves. Apoptosis was determined by Hoechst nuclear staining and by cytochrome c and caspase-8 expressions. The EMT markers E-cadherin, β-catenin, and vimentin, as well as actin and tubulin cytoskeletons, were analyzed by immunofluorescence. Interphase and mitotic microtubules as well as abnormal mitotic figures were studied by fluorescence microscopy after tubulin immunolabeling. Ukrain strongly suppressed cell proliferation and induced apoptosis possibly through an extrinsic pathway as cytochrome c immunoreactivity suggested that the integrity of the mitochondria was not affected. Tubulin expression indicated an antiproliferative effect of ukrain on the basis of alterations in mitotic spindle microtubule dynamics, leading to abnormal mitosis. Membranous E-cadherin/β-catenin immunoreactivity was similarly expressed in control-treated and ukrain-treated cells, although the drug upregulated E-cadherin in cell lysates. Our results suggest that ukrain exerts its chemotherapeutic action on PDAC cells targeting mitotic spindle microtubules, leading to abnormal mitosis and apoptosis, and favoring cell cohesiveness. The differentiated epithelial phenotype of HPAF-II, HPAC, and PL45 cell lines concomitant with a highly invasive potential suggests that further experiments will be necessary to definitively clarify the role of EMT in PDAC progression.

Epithelial-mesenchymal transition and mesenchymal-epithelial transition via regulation of ZEB-1 and ZEB-2 expression in pancreatic cancer

BACKGROUND AND OBJECTIES: Phenotypic plasticity of cancer cells via epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) is essential for tumor progression and metastasis.

METHODS

Tissue samples were obtained from 76 pancreatic head cancers. We assessed the expression of E-cadherin, vimentin, ZEB-1, and ZEB-2 by immunohistochemical and immunofluorescence staining. Next, 147 metastatic lymph nodes from 45 pancreatic cancers with low expression of E-cadherin were obtained and divided into two categories according to the maximum diameter of the metastases: 2 mm or more and less than 2 mm.

RESULTS

High expressions of ZEB-1 and ZEB-2 in the primary tumors were significantly associated with repression of E-cadherin (P = 0.0007), and poorer prognosis (P = 0.0322). Forty-three (29.3%) of the 147 metastatic tumors from pancreatic cancers with low expression of E-cadherin showed high E-cadherin expression. Cancer cells in the larger metastases showed high expression of E-cadherin (P = 0.0061) and low expression of ZEB-1 (P = 0.0170) and ZEB-2 (P = 0.0036) compared with those in the smaller metastases.

CONCLUSIONS

In primary pancreatic tumors and metastatic lymph nodes, high and low expression of ZEB-1 and ZEB-2 was associated with mesenchymal and epithelial phenotype of cancer cells, respectively.

The cytology of micropapillary variant of colloid carcinoma of breast: A report of two cases

Colloid carcinoma (pure mucinous carcinoma) is an uncommon variant of breast carcinoma with distinctive cytological and histological features. These tumors are characterised by islands of tumor cells floating in a sea of abundant extracellular mucin. We present the cytology of two cases of colloid carcinoma occurring in 80-year-old and 45-year-old females. The fine-needle aspiration cytology helps to subcategorize the tumor type, thereby enhancing the knowledge about the distinctive cytological features of special and uncommon variants of breast carcinoma, their course and prognosis. A distinctive micropapillary variant of pure mucinous carcinoma which is rarely described, is represented in one of the cases. Also we report, here, colloid carcinoma in a female of reproductive age, a relatively uncommon occurrence.

Cytologic diagnosis of pulmonary adenocarcinoma with micropapillary pattern: does it correlate with the histologic findings?

Micropapillary adenocarcinoma is associated with poor-prognosis in several organs including the lung. The presence of small tight balls of neoplastic cells devoid of fibrovascular core in cytological preparations (micropapillary tufts) has been described as characteristic of micropapillary adenocarcinoma. In the lung, however, this criterion has not been validated. The cytological material of 46 cases of histologically proven pulmonary adenocarcinoma with a micropapillary component was compared to 33 cases with no micropapillary component to determine the specificity of micropapillary tufts for the histologic diagnosis of micropapillary adenocarcinoma. Other histologic patterns of invasive pulmonary adenocarcinomas (acinar, papillary, and solid) were also compared with patterns of neoplastic cell aggregates in cytological preparations. There were no significant differences in the distribution of micropapillary clusters between the two groups. The positive predictive value for the cytologic diagnosis of a micropapillary component in lung adenocarcinomas was of 64%. Similar findings were observed for other invasive patterns. Therefore, the detection of micropapillary tufts in cytology is not specific for the diagnosis of a pulmonary micropapillary adenocarcinoma in the lung.

Prognostic Significance of Micropapillary Pattern in Pure Mucinous Carcinoma of the Breast

Breast carcinoma with micropapillary architecture is associated with aggressive behavior. Similar micropapillary pattern in pure mucinous carcinoma has been noticed and has been shown to convey poor prognosis. In this study 17 cases of pure mucinous carcinoma of the breast seen during a 10-year period have been reviewed, with special reference to micropapillary pattern. Diffuse micropapillary pattern was seen in 6 of 17 cases of mucinous carcinoma of the breast and demonstrated reverse polarity immunostaining pattern with “Epithelial Membrane Antigen.” In all cases, the tumor cells showed grade I morphology, and no lymph node metastases were noticed. All the tumors except 1 expressed strong estrogen and progesterone receptor expression, however, all the cases were negative for Her-2/neu expression. In this present study, mucinous carcinomas with micropapillary pattern showed a low nuclear grade, higher incidence of hormone receptor positivity, and lower incidence of Her-2/neu similar to mucinous carcinomas without micropapillary pattern, thus explaining their indolent behavior.

Reassessing epithelial to mesenchymal transition as a prerequisite for carcinoma invasion and metastasis

For most carcinomas, progression toward malignancy is accompanied by loss of epithelial differentiation and a shift towards a mesenchymal phenotype. This process, referred to as epithelial to mesenchymal transition (EMT), exacerbates motility and invasiveness of many cell types and is often considered a prerequisite for tumor infiltration and metastasis. However, there are numerous examples of advanced carcinomas that adopt some mesenchymal features, yet retain characteristics of well-differentiated epithelial cells. We provide a review of these reports and describe mechanisms to explain the morphologic and molecular heterogeneity and plasticity of malignant carcinoma cells, including incomplete EMT, reversion to an epithelial phenotype, and collective migration. We suggest that these mechanisms can manifest in a series of independent and reversible steps and that EMT represents just one mechanism in the global metastatic carcinoma development process.

Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast

AIM

To determine the pathognomonic diagnostic cytological features of invasive micropapillary carcinoma of the breast which is a poor prognostic subtype of infiltrating ductal carcinoma.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

A case of invasive micropapillary carcinoma of the breast

BACKGROUND

Invasive micropapillary carcinoma (IMP) of the breast is uncommon and has only recently been characterized. Knowing the cytological appearance of IMP is important to enable early diagnosis by fine needle aspiration cytology (FNAC). We describe a case of IMP diagnosed by preoperative FNAC.

CASE

A 48-year-old menopausal woman presented in 2003 with a mass in her left breast. Mammogram and ultrasound findings indicated that the tumor was malignant. Cytological examination showed papillary clusters of hyperchromatic cells with irregular and crowded nuclei, but lacking papillary cores. No myoepithelial cells were seen. Based on the cytological findings, invasive micropapillary carcinoma was diagnosed. Microscopic findings showed cancer cells with moderate atypia in abundant micropapillary cancer nests without a fibrovascular core. These cancer nests were morula-like, surrounded by empty, clear spaces lined with delicate strands of fibrocollagenous stroma. The polarity of each cancer nest was reversed, with the secretion border facing fibrocollagenous stroma. These pathological features occupied the invasive part of the primary tumor.

CONCLUSION

The cytologic features of IMP are distinctive and correlate with histology. FNAC of IMP is important role to confirm the diagnosis.

Reversal of glandular polarity in the lymphovascular compartment of breast cancer

AIM

To investigate the polarity of breast invasive ductal carcinoma cells by comparing the polarity of the tumour located within lymphovascular spaces with that located in the extravascular compartment.

METHODS

An immunohistochemical study identifying the apical HMFG-1, basolateral AUA-1, and basal laminin polarity markers of 11 cases of invasive ductal carcinoma (grades 1 or 2) metastatic to lymph nodes, all of which contained areas of tumour within and outside of lymphovascular spaces.

RESULTS

Only one of 11 tumours had a focus of apparent reversed glandular polarity in the larger extravascular tumour compartment (with AUA-1 present internally and HMFG-1 expressed externally on tumour clumps), but six of the 11 tumours showed reversed glandular polarity (either with AUA-1, or HMFG-1, or both) within the very much smaller lymphovascular space tumour compartment. Laminin was not identified in association with lymphovascular tumour.

CONCLUSIONS

Reversed glandular polarity in invasive ductal breast carcinomas was identified and was significantly more frequent within vessels than outside of them. Reversal of tumour glandular polarity within lymphovascular spaces allows direct interaction between apical domain-type molecules-which are then aberrantly expressed on the external surface of tumour clumps-and lymphovascular endothelium. Such interactions may affect the establishment of metastatic disease.