Clinicopathological characteristics of mucinous carcinoma of the breast in Korea: comparison with invasive ductal carcinoma-not otherwise specified

Double Trouble: A Rare Case of Synchronous Breast and Thyroid Carcinomas

Breast carcinoma and thyroid carcinoma are among the most common cancers affecting women. Although it is rare to encounter synchronous primary tumors of the thyroid and breast in clinical practice, the incidence of both differentiated thyroid and breast cancers has significantly risen over the last 20 years. Despite having a lower mortality risk compared to other types of cancer, managing a dual diagnosis of these malignancies poses unique challenges and requires a thorough evaluation and strategic treatment plan. Here, we report a rare case of double primary malignancy of the breast and thyroid in a 59-year-old female who presented with complaints of a lump in the left breast, along with an incidental finding of thyroid swelling, which had conflicting findings in various preliminary evaluations. In this reported case, the patient underwent a total thyroidectomy based on a frozen section report suggestive of papillary carcinoma along with a modified radical mastectomy because of mucinous carcinoma of the left breast, which by itself is a rarity. This constituted a great challenge in managing both malignancies simultaneously. In conclusion, synchronous breast and thyroid carcinomas constitute an atypical clinical scenario that requires detailed evaluation and a multidisciplinary management approach. Further research is needed to understand this condition's underlying pathophysiology and genetic background to improve therapeutic outcomes for affected individuals.

Five-year survival prognosis of young, middle-aged, and elderly adult female invasive breast cancer patients by clinical and lifestyle characteristics

PURPOSE

Early-onset breast cancer incidence has been increasing globally and in Taiwan. However, previous studies have not comprehensively examined how clinical and lifestyle characteristics influence the 5-year survival of breast cancer diagnosed at different stages of adulthood.

METHODS

We analyzed the Taiwan National Cancer Registry and Cause of Death datasets to understand how clinical factors (including tumor and treatment characteristics) and lifestyle factors (including body mass index, cigarette smoking, and alcohol consumption) were associated with the 5-year survival of 8471 young, 57,695 middle-aged, and 14,074 elderly female adult invasive breast cancer patients respectively diagnosed at age 20-39, 40-64, and ≥ 65 years between 2002 and 2015, with mortality follow-up to 2020. Poisson regression was used for obtaining the crude and adjusted 5-year survival risk ratios.

RESULTS

Clinical and lifestyle characteristics were distributed differently but had mostly similar direction of association with 5-year survival for the three age groups. Receiving any treatment was associated with better survival, especially for elderly patients. Being underweight at initial cancer treatment was associated with worse survival than having normal weight, especially for elderly patients. Current smokers had worse survival than never smokers for middle-aged and elderly patients. The 5-year breast cancer-specific survival was not significantly higher for those of age 45-49 years than 40-44 years, despite the recommended starting screening age is 45 years in Taiwan.

CONCLUSION

Our findings contribute to the understanding of early-onset and later-onset female breast cancer characteristics and prognosis, which may inform surveillance and treatment strategies to achieve better breast cancer prognosis.

Pure Mucinous Carcinoma of the Breast: Radiologic-Pathologic Correlation

Mucinous carcinoma (MC) of the breast is a rare, specialized subtype of invasive breast carcinoma (IBC) accounting for approximately 1% to 4% of all primary breast malignancies. Mucinous carcinoma occurs predominantly in patients who are postmenopausal or elderly. It is usually detected on screening mammography, but occasionally the patient may present with a palpable mass. The most common mammographic appearance is an equal to high density, oval or round mass with circumscribed or indistinct margins; MC can mimic a benign lesion. Histologically, MC is a well-differentiated cancer characterized by pools of mucin around neoplastic cells. Depending on mucin content, the tumor is classified as pure (≥90% mucin) or mixed (>10% and <90% mucin). Pure MCs (PMCs) are of low or intermediate nuclear grade, and the vast majority are hormone receptor-positive and human epidermal growth factor-2 receptor-negative (luminal A subtype). Pure MCs may be classified as hypocellular (type A) or hypercellular (type B) and have a lower rate of axillary lymph node involvement and more favorable prognosis than IBCs, no special type. The purpose of this article is to review the clinical features, imaging appearances, associated histopathology, and management of PMC.

A novel nomogram and risk classification system for predicting lymph node metastasis of breast mucinous carcinoma: A SEER-based study

BACKGROUND

Mucinous breast cancer (MBC) is a rare disease, and patients with lymph node metastasis (LNM) have a poor prognosis. We aimed to explore the predictive factors of LNM and to construct a nomogram for predicting the risk of LNM and to identify the suitable axillary surgery for patients with diverse risks.

PATIENTS AND METHODS

Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Chi-square and rank-sum tests were used to analyze the differences between groups. Survival analysis was performed with Kaplan-Meier curves and log-rank tests. Independent factor identification and nomogram construction were performed with logistic regression analysis. The nomogram was qualified with a discrimination and calibration plot. Propensity score matching was performed to balance the disparities between groups.

RESULTS

Patients with metastatic lymph nodes have a worse prognosis. Univariate and multivariate analyses indicated that tumor size, grade, and age were independent risk factors for LNM. The nomogram constructed with these three factors can predict the risk of LNM with high accuracy (AUC: 0.767, 95% CI: 0.697-0.838) and good calibration. Based on the nomogram, a risk classification system satisfactorily stratified the patients into 3 groups with diverse risks of LNM. In the low-risk group, there were no significant differences between sentinel lymph node biopsy and no axillary surgery. In the middle- and high-risk groups, both SLNB and axillary lymph node dissection were superior to no axillary surgery, with similar survival benefits.

CONCLUSIONS

The nomogram based on tumor size, grade, and age could conveniently and accurately predict the risk of LNM in MBC and assist clinicians in optimizing surgical strategies.

The clinical features and prognosis of patients with mucinous breast carcinoma compared with those with infiltrating ductal carcinoma: a population-based study

BACKGROUND

At present, the characteristics of mucinous breast carcinoma (MBC) and the factors affecting its prognosis are controversial. We compared the clinical features of MBC with those of infiltrating ductal carcinoma (IDC) and summarized the relevant prognostic factors.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database includes information on 10,593 patients diagnosed with MBC between 2004 and 2016. Chi-square tests and analyses were used to analyze differences in variables between the MBC and IDC groups. Univariate and multivariate Cox proportional hazards models were used to assess the relative impacts of risk factors on cancer-specific survival (CSS) in patients. Kaplan-Meier survival curves were constructed to assess cancer-specific mortality and were compared using the log-rank test.

RESULTS

From 2004 to 2016, 10,593 people were diagnosed with MBC, and 402,797 were diagnosed with IDC. Patients with MBC had significantly higher 5-/10-year CSS rates (96.4%/93.4%) than those with IDC (89%/83.8%). Compared with IDC patients, MBC patients had less lymph node metastasis, an earlier stage, a higher rate of hormone receptor positivity and a lower expression rate of HER2. Univariate and multivariate analyses showed that age ≥ 60 years old (HR = 1.574, 95%CI: 1.238-2.001, P < 0.001), singled status (HR = 1.676, 95%CI: 1.330-2.112, P < 0.001) and advanced TNM/SEER stage were independent prognostic risk factors for MBC. In addition, positive estrogen receptor (HR = 0.577, 95%CI: 0.334-0.997, P = 0.049), positive progesterone receptor (HR = 0.740, 95%CI: 0.552-0.992, P = 0.044), surgical treatment (HR = 0.395, 95%CI: 0.288-0.542, P < 0.001) and radiotherapy (HR = 0.589, 95%CI: 0.459-0.756, P < 0.001) were identified as protective factors.

CONCLUSION

Compared with IDC, MBC has a better prognosis. For patients with MBC, we identified prognostic factors that can help clinicians better assess patient outcomes and guide individualized treatment.

Histopathological analysis of mucinous breast cancer subtypes and comparison with invasive carcinoma of no special type

Mucinous breast cancer (MBC) is a rare histological type of breast cancer characterized primarily by mucin's production and extracellular presence. MBC is usually associated with a better prognosis than other invasive breast neoplasms. Because of the low prevalence, MBC biology is not well understood. The aim of the present study was to introduce the last 2-year experience regarding MBC pathological diagnostics in our clinical center and comparison of the obtained data with invasive breast carcinoma of no special type (NST) comprising the most common invasive breast cancer. We identified 24 MBC cases representing 3.09% of all 766 invasive breast cancers, including 15 cases of pure type and 9 mixed MBCs. The median MBC patients' age at presentation was 65.5 years. Compared to NST, MBC presented a higher T stage with a statistically larger tumor median size, although lower regional lymph node involvement, tumor histological grade and TNM stage. MBC is a rare type of breast cancer, accounting for about 4% of all diagnosed breast cancers. Our findings are consistent with those published in recent years and show significant differences between MBC and NST cancer patients and also highlight differences between pure and mixed MBC, emphasizing the essence of their differentiation. MBC is associated with a better long-term prognosis than NST and is characterized by the less aggressive biological behavior expressed through favorable clinicopathologic features in terms of tumor grade, regional lymph node involvement and hormone receptor status.

Comparison of the Distribution Pattern of 21-Gene Recurrence Score between Mucinous Breast Cancer and Infiltrating Ductal Carcinoma in Chinese Population: A Retrospective Single-Center Study

Purpose

This retrospective study aimed to evaluate the distribution pattern and prognostic value of 21-gene recurrence score (RS) in Chinese patients with mucinous breast cancer (MC) and compared with infiltrating ductal carcinoma (IDC).

Materials and Methods

Patients diagnosed with MC or IDC from January 2010 to January 2017 were retrospectively recruited. Reverse transcriptase–polymerase chain reaction assay of 21 genes was conducted to calculate the RS. Univariate and multivariate analyses were performed to assess the association between RS and clinicopathological factors. Survival outcomes including disease-free survival (DFS) and overall survival (OS) were estimated by Kaplan-Meier method and compared by log-rank test.

Results

The MC cohort included 128 patients and the IDC cohort included 707 patients. The proportions of patients with a low (RS < 18), intermediate (18-30), or high risk (RS > 30) were 32.0%, 48.4%, and 19.5% in MC cohort, and 26.9%, 46.8% and 26.3% in IDC cohort. The distribution of RS varied significantly according to different Ki-67 index and molecular subtype in both cohorts. Moreover, the receipt of chemotherapy was associated with RS in both cohorts. Among patients with MC, tumor stage was related to the DFS (p=0.040). No significant differences in DFS and OS were found among MC patients in different RS risk groups (OS, p=0.695; DFS, p=0.926).

Conclusion

RS was significantly related to Ki-67 index and molecular subtypes in MC patients, which is similar in IDC patients. However, RS was not able to predict DFS and OS in patients with MC.

Omission of adjuvant radiotherapy following breast-conserving surgery for elderly women with early-stage pure mucinous breast carcinoma

Background

We aimed to ascertain population-based practice patterns and survival outcomes of postoperative radiotherapy following breast conserving-surgery (BCS) in elderly women (aged ≥65 years) with early-stage pure mucinous breast carcinoma (PMBC).

Methods

Patients aged ≥65 years diagnosed with T1–2N0 and hormone receptor-positive PMBC between 1990 and 2010 were identified from the Surveillance, Epidemiology, and End Results database. Binomial logistic regression, Kaplan-Meier method, Multivariate Cox proportional hazards models, and propensity score matching (PSM) were used for statistical analysis.

Results

We enrolled 3416 patients, including 1225 (35.9%) and 2191 (64.1%) in the no-radiotherapy and radiotherapy cohorts, respectively. The percentage of patients receiving postoperative radiotherapy following BCS was significantly lower after 2004 (59.5% between 2004 and 2010), relative to that before 2004 (71.1% between 1990 and 2003; P < 0.001). Before PSM, the 10-year breast cancer-specific survival (BCSS) rates were 98.1 and 93.2% for patients with and without postoperative radiotherapy (log-rank test, P < 0.001), respectively. In the PSM cohort, receiving postoperative radiotherapy was associated with better BCSS rates, with 10-year BCSS rates of 97.6 and 94.5% in patients with and without postoperative radiotherapy, respectively (log-rank test, P = 0.001). Multivariate Cox proportional analysis indicated that receiving postoperative radiotherapy was an independent factor associated with better BCSS before (P < 0.001) and after PSM (P = 0.001), relative to those not receiving postoperative radiotherapy.

Conclusions

This study shows a decreasing utilization of postoperative radiotherapy following BCS of elderly PMBC patients over time. However, postoperative radiotherapy following BCS should be administered for elderly women with PMBC owing to independent association with better survival.

Clinical Implication of HER2 Status in Hormone Receptor-Positive Mucinous Breast Cancer

PURPOSE

Mucinous carcinoma (MC) is a rare breast cancer with favorable outcome. Unlike typical breast cancer, the current guidelines do not recommend chemotherapy or anti-human epidermal growth factor receptor 2 (HER2) therapy for hormone receptor (HR)-positive MC, regardless of HER2 status. We evaluated the prognostic implication of HER2 status in HR-positive MC.

METHODS

We retrospectively reviewed the data of 471 patients with pure MC (stages I-III) who underwent curative surgery. We analyzed 5-year disease-free survival (DFS) and distant metastasis-free survival (DMFS), according to clinicopathological characteristics.

RESULTS

The median follow-up duration was 79.0 months. Overall, the 5-year DFS rate was 95.7% and the 5-year DMFS rate was 96.2%. Nodal status was the only significant factor for DFS (relative risk [RR], 3.40; 95% confidence interval [CI] 3.40-9.67, p = 0.021). Among HR-positive/node-negative patients with tumor size ≥ 3 cm, HER2-positive patients showed significantly worse DFS (RR, 8.76; 95% CI 1.45-52.76, p = 0.018) and DMFS (RR, 11.37; 95% CI 1.37-74.70, p = 0.011). This finding was consistently significant, when combining both "HR-positive/node-negative/tumor size ≥ 3 cm" and "HR-positive/node-positive" MC (n = 125) for DFS (RR, 4.30; 95% CI 1.43-12.97, p = 0.009) and DMFS (RR, 4.93; 95% CI 1.63-14.90, p = 0.005). Intriguingly, within this subgroup, among HER2-positive tumors, whereas 5-year DFS was 60.2% in patients who did not receive trastuzumab, 100% of those who received trastuzumab were disease free (p = 0.053).

CONCLUSIONS

In HR-positive, node-negative MC with tumor size ≥ 3 cm, patients with HER2-positive MC showed worse survival, suggesting a potential role of an anti-HER2 strategy in this subgroup.

Predictors for Survival and Distribution of 21-Gene Recurrence Score in Patients With Pure Mucinous Breast Cancer: A SEER Population-Based Retrospective Analysis

BACKGROUND

Pure mucinous breast cancer (PMBC) is a rare pathologic type of breast cancer, the prognostic factors of which have not been clearly defined. This study aimed to analyze the prognostic markers and distribution of 21-gene recurrence score (RS) in patients with PMBC.

PATIENTS AND METHODS

Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, a retrospective analysis of PMBC cases was conducted. Multivariate analyses were used to evaluate the indicators for prognosis and the correlations between RS and traditional clinicopathologic characteristics. Disease was subdivided into 4 molecular phenotypes using estrogen receptor (ER) status and tumor grade.

RESULTS

Of the 8048 patients, most had ER-positive and node-negative tumors. Multivariate analysis revealed that molecular phenotype as well as age, race, tumor size, and lymph node status was an independent prognostic factor for patients with PMBC (P < .05). The 5-year breast cancer-specific survival of patients among different phenotypes was significantly different (97.9% for ER-positive and grade I tumor, 96.9% for ER-positive and grade II-III tumor, 96% for ER-negative and grade I tumor, 90.1% for ER-negative and grade II-III tumors, P < .001). The proportions of patients categorized into low, intermediate, and high RS risk group were 64.9%, 31.9%, and 3.2%, respectively. Grade, progesterone receptor status, and age were identified as independent variables associated with RS.

CONCLUSION

PMBC had favorable biological features and relatively good prognosis. Molecular phenotype as well as age, race, tumor size, and lymph node status were independent prognostic markers. Furthermore, age, progesterone receptor status, and grade could independently predict RS.

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.

Her-2 positive mucinous carcinoma breast cancer, case report

INTRODUCTION

Mucinous carcinoma is a variant of invasive breast carcinomas that accounts for 2% of them and has a better prognosis in contrast to the non-specific invasive carcinoma. They regularly are positive for estrogen and progesterone receptors and, generally, they do not overexpress HER2. When HER2 is positive, the first line treatment is trastuzumab; although the resistance is 52-89% for the non-specific carcinoma, it has been described just once in mucinous carcinoma.

CASE SUMMARY

A 48-year-old female presented with a lump in her right breast and after a biopsy, it was diagnosed as mucinous carcinoma in the core biopsy and surgical resection, with positive hormone receptors and HER2 positive (3+) in 100% of the tumor cells. She was treated with neoadjuvant chemotherapy based on trastuzumab and pertuzumab with no pathological response.

DISCUSSION

There are few pure mucinous carcinomas positive for HER2. Mucinous carcinomas are positive for HER2 account for less than 5% of invasive ductal carcinoma. Furthermore, our case was resistance to chemotherapy. Most mucinous carcinomas test negative for HER2, so they usually would not be treated with trastuzumab, in this case because the expression of HER2 in the biopsies we initiated it.

CONCLUSION

It's important to know that cases of mucinous carcinoma positive for HER2 exist and to be aware of the clinical problems that they may present: resistance to trastuzumab. Also, we need to understand the responsible mechanisms of this resistance and use immunohistochemistry for MUC which may predict it.

Expression of vascular endothelial growth factor and caspase-3 in mucinous breast carcinoma and infiltrating ductal carcinoma-not otherwise specified, and the correlation with disease-free survival

Mucinous breast carcinoma (MBC) is a rare type of breast cancer, but it has been infrequently studied due to its associated good prognosis. Vascular endothelial growth factor (VEGF) and caspase-3 have been identified to be prognostic factors of infiltrating ductal carcinoma-not otherwise specified (IDC-NOS), but their expression in MBC has not been reported. In the present study, the expression of caspase-3 and VEGF in MBC and IDC-NOS were assessed by immunohistochemistry. Scoring was conducted based on staining intensity and percentage of positive cells. Based on the scores of caspase-3 and VEGF expression, all patient samples were divided into two groups: Low expression (score of 0-5) or high expression (score of 6-12). In total, 42.59% of MBC patients exhibited a high VEGF score compared with 61.67% of the IDC-NOS group (P<0.05). Furthermore, 57.41% of MBC patients exhibited high caspase-3 expression compared with only 33.33% of IDC-NOS patients (P<0.05). VEGF expression in MBC was associated with age, nodal status and tumor-node-metastasis (TNM) stage. Cox univariate analysis showed that higher VEGF expression, positive nodal status and higher TNM stage were associated with shorter disease-free survival (DFS). The Kaplan-Meier method showed that higher VEGF expression in MBC was associated with worse DFS times, while Cox multivariate analysis showed that only TNM stage was significantly associated with DFS. VEGF and caspase-3 expression varied in the MBC and IDC-NOS samples, but neither was directly correlated with DFS in the MBC patients.

Clinicopathological Characteristics of Mucinous Breast Cancer: A Retrospective Analysis of a 10-Year Study

Background

Mucinous breast carcinoma (MC) is a special type of breast cancer that presents with a large amount of extracellular mucin. MC comprises approximately 4% of all invasive breast cancers. This type of tumor has a better prognosis and higher incidence in peri- and post-menopausal patients. Pathologically, there are two main subtypes of MC: pure and mixed. In this study, we describe 10 years of experience with MC at the Zhejiang Cancer Hospital in China, specifically, clinical data, histological findings and immunohistochemical features.

Methods

We identified MC patients who were diagnosed as operable and completed clinical treatment from January 2001 to January 2011. The clinicopathological data included the age at diagnosis, tumor size, TNM stage, presence and number of lymph node (LN) metastases, estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2) status and p53 expression. If the tumor was defined as mixed mucinous carcinoma (MMC), IHC was performed on a non-mucinous part, such as invasive ductal and lobular cancer. We evaluated the clinical characteristics of all MC patients using chi-square, one-way ANOVA and LSD tests. We also studied the correlations between all of the clinical parameters and LN metastasis in a binary logistic regression analysis. We used ten consecutive years of data that were collected at Zhejiang Cancer Hospital.

Results

We identified 48 cases of pure mucinous carcinoma (PMC) and 77 cases of MMC. The 48 PMC cases consisted of 38 PMC-A and 10 PMC-B subtypes. The MMCs were divided into two groups, those with partial mixed mucinous breast carcinoma (pMMC, 58 cases) and those with main mixed mucinous breast carcinoma (mMMC, 19 cases). pMMC was defined by tumors with less than 50% mucinous components, while mMMC was defined by tumors where the mucinous component accounted for 50% to 90% of the tumor. No significant differences in the clinicopathological characteristics were noted between the patients with PMC-A and those with PMC-B. The tumor size was larger in the mMMC than PMC cases (44.84 mm vs. 30.06 mm, p = 0.021). The number of positive LN metastases was greater in pMMC than PMC patients (p = 0.024). The clinical stages were significantly different among the three groups, with the pMMC group having more stage III-IV patients than the other two groups (p = 0.005). The incidence of LN metastasis was also higher in the pMMC cases (pMMC vs. mMMC and PMC, 50% vs. 31.58% and 18.75%, p = 0.003). The PMC patients had much lower p53 expression than the other two groups (PMC vs. pMMC and mMMC, 27.08% vs. 55.17% and 57.89%, p = 0.007). The tumor size (>30mm), p53 expression and less proportion of the mucinous component are associated with risk of LN metastasis.

Conclusion

Based on the results of this study, we conclude that the tumor size, status of LN metastasis, clinical stage, and p53 mutation rate may differ between MMC and PMC patients. The tumor size (>30mm), p53 mutation and less proportion of the mucinous component should be considered risk factors of LN metastasis in MC patients.

Two cases of matrix-producing carcinoma showing chondromyxoid matrix in cytological specimens

Matrix-producing carcinoma (MPC) is extremely rare. Limited reports have described the cytological aspects of MPC. Herein, we present 2 cases of MPC, both of which showed ring-enhancement on magnetic resonance imaging (MRI) and chondromyxoid matrix on cytological specimens. In these cases, the diagnosis of MPC was preoperatively suspected. Recognizing extracellular matrix as chondromyxoid matrix on the cytological specimen is important in making a distinction between MPC and mucinous carcinoma. They share some features on cytology and MRI (ring-enhancement) but have different prognoses and involve different approaches for obtaining histological specimens for neoadjuvant therapy. The reason for the different approaches for obtaining the histological specimens is that tumor cells usually distribute peripherally in MPC in contrast to the relatively uniform distribution of mucinous carcinoma. Therefore, it would be helpful if the diagnosis of MPC can be suspected by examination of the cytological specimen.

The molecular background of mucinous carcinoma beyond MUC2

The increasing interest of the oncology community in tumour classification and prediction of outcome to targeted therapies has put emphasis on an improved identification of tumour types. Colorectal mucinous adenocarcinoma (MC) is a subtype that is characterized by the presence of abundant extracellular mucin that comprises at least 50% of the tumour volume and is found in 10–15% of colorectal cancer patients. MC development is poorly understood, however, the distinct clinical and pathological presentation of MC suggests a deviant development and molecular background. In this review we identify common molecular and genetic alterations in colorectal MC. MC is characterized by a high rate of MUC2 expression. Mutation rates in the therapeutically important RAS/RAF/MAPK and PI3K/AKT pathways are significantly higher in MC compared with non‐mucinous adenocarcinoma. Furthermore, mucinous adenocarcinoma shows higher rates of microsatellite instability and is more frequently of the CpG island methylator phenotype. Although the majority of MCs arise from the large intestine, this subtype also develops in other organs, such as the stomach, pancreas, biliary tract, ovary, breast and lung. We compared findings from colorectal MC with tumour characteristics of MCs from other organs. In these organs, MCs show different mutation rates in the RAS/RAF/MAPK and PI3K/AKT pathways as well, but a common mucinous pathway cannot be identified. Identification of conditions and molecular aberrations that are associated with MC generates insight into the aetiology of this subtype and improves understanding of resistance to therapies.

Pure mucinous breast carcinoma: a favorable subtype

BACKGROUND

Pure mucinous breast carcinoma is a relatively rare subtype of breast malignancy. This study is to investigate the clinical and pathologic features of pure mucinous breast carcinoma.

PATIENTS AND METHODS

A retrospective review of our database of patients who presented with breast cancer was performed. The medical records of 1,060 patients with invasive breast cancer who underwent surgery were reviewed.

RESULTS

28 patients with pure mucinous breast cancer were identified. The mean age was 55.28 ± 15.73 years. 17 patients underwent modified radical mastectomy; 11 underwent breast-conserving therapy. The tumor size was T1 in 19 patients, T2 in 8 patients, and T3 in 1 patient. None of the patients had lymph node metastasis. There was no distant metastasis. 18 were stage I, and 10 were stage II. Estrogen receptor, progesterone receptor, HER-2, and P53 were positive in 96, 93, 0, and 28%, respectively. Median follow-up was 42 months (range 1-84 months). 1 patient had local recurrence. The overall survival rate was 100%.

CONCLUSION

Pure mucinous breast carcinoma has a favorable prognosis. Less invasive treatment might be optional. Larger data samples with longer follow-up would be necessary to gain a better understanding of this disease.

Outcome of pure mucinous breast carcinoma compared to infiltrating ductal carcinoma: a population-based study from China

PURPOSE

Pure mucinous breast carcinoma (PMBC) is a rare pathologic finding. Few studies have addressed the biologic features of PMBC and prognostic factors among patients with this disease. We performed a study to compare PMBC and invasive ductal carcinoma (IDC) by means of a large database to reliably assess the biologic phenotype and clinical behavior of PMBC.

METHODS

A total of 2,511 patients who met the inclusion criteria were identified from 1999 to 2010; 2,202 patients had pure IDC and 309 had PMBC. Clinical and biologic features, overall survival, and recurrence/metastasis-free survival (RFS) were compared for both groups.

RESULTS

PMBC had favorable characteristics including smaller size, lower rates of lymph node positivity, lower stage, higher expression of hormone receptors, and less HER2 overexpression. Patients with PMBC had better 10-year RFS (71 %) than patients with IDC (64 %). Multivariate analysis revealed that node status and tumor, node, metastasis system (TNM) stage were statistically significant prognostic factors for survival. RFS curves stratified for node status revealed a highly significant difference between node negative and node positive patients. Additionally, patients with PMBC underwent breast-conserving surgery (BCS) more frequently than patients with IDC, and the 5-year overall survival rate of the BCS group was not significantly different from the total mastectomy group.

CONCLUSIONS

PMBC in Chinese women showed less aggressive behavior and had a better prognosis than IDC, and this favorable outcome was maintained after 10 years. Node status and TNM stage appeared to be the most significant predictors of worse prognosis. BCS should be preferred over mastectomy in the treatment of early-stage PMBC.

Mucinous carcinoma of the breast in comparison with invasive ductal carcinoma: clinicopathologic characteristics and prognosis

Purpose

Mucinous carcinoma (MC) of the breast is a rare histologic type of mammary neoplasm. The objective of this study was to evaluate the long-term disease-free survival (DFS) and overall survival (OS) of MC.

Methods

We conducted a retrospective analysis of all MC cases reported to a database between 1994 and 2010. Clinicopathological characteristics and survival of 268 MC cases were reviewed and compared with 2,455 invasive ductal carcinoma-not otherwise specified (IDC-NOS) cases.

Results

The MC cases were of a younger age, involved less lymph nodes, lower stage, more expression of hormonal receptors, and less HER2 overexpression compared to the IDC-NOS cases. The 5-year DFS rate for MC was 95.2% compared to 92.0% for IDC-NOS. The 5-year OS rate for MC was 98.9% compared to 94.9% for IDC-NOS. Multivariate analysis using Cox regression revealed that the mucinous type was a significant prognostic factor for DFS with lower nodal status (N stage) and hormonal therapy. For OS, only N stage was the most significant prognostic factor followed by adjuvant chemotherapy and adjuvant hormonal therapy.

Conclusion

MC was shown to be associated with a better DFS than IDC-NOS, but it had a similar OS. Nodal status and adjuvant therapy appear to be more significant predictors of prognosis than histologic subtype.