Pure and Mixed Mucinous Carcinoma of the Breast: A Comparison of Clinical Outcomes and Treatment Results

Clinicopathological characteristics and genomic profiling of pure mucinous breast cancer

PURPOSE

Pure mucinous breast cancer (PMC) is a rare histological type with a favourable prognosis. However, cases with recurrence have been reported and diagnosed in clinical practice. The mechanisms underlying PMC recurrence remain unknown. In this study, we aimed to identify the prognostic factors associated with PMC.

MATERIALS AND METHODS

A total of 166 patients diagnosed with PMC were included. We compared the clinicopathological characteristics between patients with and without recurrence. The 21-gene assay was performed in 10 patients with recurrence and 20 TNM stage-matched patients without recurrence. Whole-exon sequencing was performed in 12 PMC primary tumours and four positive lymph nodes (LNs).

RESULTS

Tumour size, lymph node status and TNM staging differed significantly between recurrent group and non-recurrent group. And the 21-gene recurrence scores did not differ significantly between recurrent group and its TNM stage-matched non-recurrent group. The most frequently mutated genes in the primary tumours of regional LN-positive PMCs were ADCY10 (3/6) and SHANK3 (3/6), and they more recurrently harboured gains of 15q23, 17q23.2 and 20p11.21, and loss of 21p11.2. And these alterations were not detected in primary tumours of regional LN-negative PMCs.

CONCLUSION

TNM stage is an important prognostic factor in PMC. Although we revealed that regional LN-positive PMCs show increased occurrence of duplication variants at 15q23, 17q23.2 and 20p11.21, and deletion variants at 21p11.2. Further investigation, including multi-omics studies, are needed and may provide additional insights into the nature of PMC.

An Effective Ultrasound Features-Based Diagnostic Model via Principal Component Analysis Facilitated Differentiating Subtypes of Mucinous Breast Cancer From Fibroadenomas

BACKGROUND

Mucinous breast carcinoma (MBC) is often misdiagnosed as fibroadenoma (FA),which can lead to inappropriate or delayed treatments. This study aimed to establish an efficient ultrasound (US)-based diagnostic model to distinguish MBC subtypes from FAs.

METHODS

Between January 2017 and February 2024, 240 lesions were enrolled, comprising 65 cases of pure mucinous breast carcinoma (PMBC), 47 cases of mixed mucinous breast carcinoma (MMBC), and 128 cases of FAs. Ten US feature variables underwent principal component analysis (PCA). Models were constructed based on components explaining over 75% of the total variation, with varimax rotation applied for interpretability. Comprehensive models were developed to distinguish PMBCs and MMBCs from FAs.

RESULTS

Six principal components were selected, achieving a cumulative contribution rate of 77.46% for PMBCs vs. FAs and 78.62% for MMBCs vs. FAs. The principal component of cystic-solid composition and posterior acoustic enhancement demonstrated the highest diagnostic value for distinguishing PMBCs from FAs (AUC: 0.86, ACC: 80.31%). Features including vascularization, irregular shape, ill-defined border, and larger size exhibited the highest diagnostic value for distinguishing MMBCs from FAs (AUC: 0.90, ACC: 87.43%). The comprehensive models showed excellent clinical value in distinguishing PMBCs (AUC = 0.86, SEN = 86.15%, SPE = 73.44%, ACC = 77.72%) and MMBCs (AUC = 0.92, SEN = 80.85%, SPE = 95.31%, ACC = 91.43%) from FAs.

CONCLUSION

This diagnostic model holds promise for effectively distinguishing PMBCs and MMBCs from FAs, assisting radiologists in mitigating diagnostic biases and enhancing diagnostic efficiency.

Breast cancer and its therapeutic targets: A comprehensive review

Breast cancer is a common and deadly disease, so there is a constant need for research to find efficient targets and therapeutic approaches. Breast cancer can be classified on a molecular and histological base. Breast cancer can be divided into ER (estrogen receptor)-positive and ER-negative, HER2 (human epidermal growth factor receptor2)-positive and HER2-negative subtypes based on the presence of specific biomarkers. Targeting hormone receptors, such as the HER2, progesterone receptor (PR), and ER, is very significant and plays a vital role in the onset and progression of breast cancer. Endocrine treatments and HER2-targeted drugs are examples of targeted therapies now being used against these receptors. Emerging immune-based medicines with promising outcomes in the treatment of breast cancer include immune checkpoint inhibitors, cancer vaccines, and adoptive T-cell therapy. It is also explored how immune cells and the tumor microenvironment affect breast cancer development and treatment response. The major biochemical pathways, signaling cascades, and DNA repair mechanisms that are involved in the development and progression of breast cancer, include the PI3K/AKT/mTOR system, the MAPK pathway, and others. These pathways are intended to be inhibited by a variety of targeted drugs, which are then delivered with the goal of restoring normal cellular function. This review aims to shed light on types of breast cancer with the summarization of different therapeutic approaches which can target different pathways for tailored medicines and better patient outcomes.

Nomogram for predicting survival in patients with mucinous breast cancer undergoing chemotherapy and surgery: a population-based study

BACKGROUND

The prognosis of patients with mucinous breast cancer (MuBC) is affected by several factors, but the low incidence of MuBC makes it difficult to conduct extensive and in-depth studies. This study was designed to establish a prognostic model and verify its accuracy in patients with MuBC after chemotherapy and surgery to help develop personalized treatment strategies.

MATERIALS AND METHODS

Patients with MuBC who underwent chemotherapy and surgery from 2004 to 2015 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. The prognostic factors of patients with MuBC were investigated using a Cox proportional hazards regression analysis. Based on the identified factors, a nomogram was constructed to forecast the overall survival (OS) of patients at 3, 5, and 10 years. Internal (from SEER) and external (from Yunnan Cancer Center, YNCC) verification queues were used to verify the nomogram and demonstrate the predictive capacity of this model.

RESULTS

The study comprised 1668 MuBC patients from the SEER database and 107 from the YNCC. The nomogram included four characteristics: age, anatomical stage, surgical method, and radiotherapy. The concordance indices in the training, internal verification, and external verification queues were 0.680, 0.768, and 0.864, respectively. The calibration curves for the nomogram showed excellent agreement between the predictions and observations. This nomogram has good clinical application value according to the decision curve analysis.

CONCLUSIONS

The prognosis of patients with MuBC who have undergone chemotherapy and surgery can be forecasted using this nomogram, which would be beneficial to help create individualized treatment plans for the affected patients.

Spectrum of Mucin-containing Lesions of the Breast: Multimodality Imaging Review with Pathologic Correlation

Mucin-containing lesions of the breast encompass a wide range of benign and malignant processes. The spectrum of histologic findings includes incidental mucus-filled benign cysts or ducts, mucocele-like lesions (MLLs), mucin-producing ductal carcinoma in situ, and invasive mucinous carcinoma. MLL is characterized by the presence of mucin-containing cysts that are typically associated with extravasated stromal mucin. MLL is often benign but can be associated with epithelial atypia or malignancy. Mucinous carcinoma represents the malignant end of the spectrum of mucinous lesions of the breast. Evidence-based literature supports a conservative approach for benign MLLs without associated atypia or malignancy, reserving excision for those lesions exhibiting such pathologic features. The most common imaging finding for MLL is microcalcifications at mammography. No specific imaging feature is predictive of malignant outcome at surgical excision. Invasive mucinous carcinoma is a heterogeneous breast tumor subtype, as defined according to the World Health Organization criteria. Mucinous carcinomas are categorized into pure (>90% mucinous component) or mixed (10%-90% mucinous component) subtypes. Pure mucinous carcinomas are generally associated with excellent prognosis and survival, with a few exceptions. Mixed mucinous carcinomas do not have the same favorable prognosis and instead behave similarly to invasive breast carcinomas of no special type. Characteristic diagnostic imaging features can be identified for mucinous carcinoma based on its mucinous and nonmucinous contents. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

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.

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.

Effect of postoperative radiotherapy in women with localized pure mucinous breast cancer after lumpectomy: a population-based study

Purpose

Pure mucinous breast cancer is a rare subtype of invasive breast cancer with favorable prognosis, in which the effect of postoperative radiotherapy remains unclear. We aimed to investigate the prognostic value of postoperative radiotherapy in women with localized pure mucinous breast cancer after lumpectomy.

Methods

We conducted a retrospective cohort study to compare the effectiveness of postoperative radiotherapy (RT) and omitting postoperative radiotherapy (non-RT) in patients with first primary T1-2N0M0 (T ≤ 3 cm) pure mucinous breast cancer who underwent lumpectomy between 1998 and 2015 using the Surveillance, Epidemiology, and End Results (SEER) database. Breast cancer-specific survival (BCSS) was compared between RT and non-RT groups using Kaplan–Meier method and Cox proportional hazards regression model. Propensity score matching (PSM) was carried out to balance cohort baselines. In addition, an exploratory analysis was performed to verify the effectiveness of RT in subgroup patients.

Results

Of 7832 eligible patients, 5352 (68.3%) underwent lumpectomy with postoperative RT, 2480 (31.7%) received lumpectomy without postoperative RT. The median follow-up duration was 92 months. The median age was 66 years in the RT group and 76 years in the non-RT group.The 15-year BCSS was 94.39% (95% CI, 93.08% to 95.35%) in the RT group versus 91.45%(95% CI, 88.93% to 93.42%) in the non-RT group (P < 0.001). The adjusted hazard ratio for BCSS was 0.64 (95% CI, 0.49 to 0.83; P = 0.001) for RT group versus non-RT group. After propensity score matching, similar results were yielded. Adjuvant RT reduced the 15-year risk of breast cancer death from 7.92% to 6.15% (P = 0.039). The adjusted hazard ratio for BCSS were 0.66 (95%CI, 0.47 to 0.92; P = 0.014) for RT group versus non-RT group. The benefit of RT was well consistent across subgroup patients.

Conclusion

Among women with T1-2N0M0 (tumor size ≤ 3 cm) pure mucinous breast cancer, the addition of RT after lumpectomy was significantly associated with a reduced incidence of breast cancer death compared with non-RT, and the magnitude of benefit may be modest. This suggests that postoperative RT is recommended in the treatment of localized pure mucinous breast cancer.

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.

Construction of a Prognostic Nomogram Model for Patients with Mucinous Breast Cancer

Objective

The objective of the study is to develop a nomogram for estimating three- and five-year survival rates in mucinous breast cancer patients.

Methods

Between 2010 and 2016, the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) were searched as a data source for patients associated with mucinous breast cancer (MBC). A total of 3964 patients were recruited after screening. The multivariate Cox model and the univariate Kaplan-Meier (KM) approach were employed to evaluate the independent prognostic markers, followed by developing a nomogram for estimating three- and five-year survival rates in MBC patients. Consequently, the consistency index (C-index) was employed to assess the predictive accuracy of the generated nomogram.

Results

Age, race, T stage, M stage, surgery, and radiotherapy were all independent predictive biomarkers for the MBC patients (P < 0.05). The nomogram was finally developed based on the underlined factors. Furthermore, the C-index of 0.803 and reliable calibration curves were obtained in the nomogram's assessment.

Conclusions

In patients with mucinous breast cancer, the proposed nomogram provides a viable tool for accurate prognostic prediction. In clinical practice, it could serve as a personalized diagnosis tool, estimate prognosis, and help in suggesting treatment plans for patients with MBC.

Radiation Therapy for Advanced Mucinous Carcinoma of the Breast With a Malignant Wound: A Case Report

Patients with breast cancer who refuse standard treatment often suffer from malignant wounds due to the growth of local tumors. However, treatment strategies for patients with unresectable locally advanced breast cancer who refuse standard treatment remain unclear. Usually, such cases are treated with palliative irradiation and do not achieve local control by irradiation alone. This is the first case report discussing the role of high-dose local irradiation and the treatment course for a patient with a massive breast tumor (mucinous adenocarcinoma) who refused standard treatment. A 44-year-old female was diagnosed with mucinous carcinoma of the breast in the right breast (cT1N0M0, cStage I). She refused standard treatment for six years. She visited the emergency department because of acute bleeding from the right breast with malignant wounds. Macroscopically, the tumor in the right breast measured over 20 cm in diameter. The tumor was exudative, exhibited ulceration and slight bleeding, and emitted an odor. Imaging findings showed multiple lymph nodes and bone metastases, and the final diagnosis was stage IV breast cancer (cT4bN1M1). Although the surgeon recommended chemotherapy for breast cancer, the patient refused chemotherapy or other therapy due to concerns regarding treatment-related complications. Considering the symptoms of advanced breast cancer with malignant wounds, she finally agreed to receive radiation therapy (RT). We performed RT at 70 Gy in 35 fractions over seven weeks. The tumor-associated symptoms disappeared after RT. Three months after RT, the tumor had almost disappeared. We administered luteinizing hormone-releasing hormone agonists after RT. Two years after RT, she died due to multiple liver metastases and ascites; however, there was no disease progression in the right breast. High-dose RT for locally advanced mucinous carcinoma of the breast with malignant wounds is considered an effective therapeutic option.

Overall Survival in Patients with Mucinous Carcinoma of Breast: A Population-Based Study

Purpose

Mucinous carcinoma of the breast (MCB) is a rare malignant tumour. Therefore, it is urgent to establish a survival prediction model for MCB patients.

Methods

Clinicopathological and follow-up data of MCB patients diagnosed between 2010 and 2015 were retrieved from the Surveillance, Epidemiology, and End Result (SEER) database. The significant factors were screened out and generated Kaplan-Meier (K-M) curves for each prognostic factor. Additionally, these factors were then utilized to build a nomogram for predicting 3-, 4-, and 5-year overall survival (OS) of MCB patients. The nomogram was evaluated using calibration curves, receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

Results

Moreover, a total of 4326 MCB patients were retrieved. Age, American Joint Committee on Cancer (AJCC) stage, surgery, radiotherapy and bone metastasis were identified as independently prognosis factors for OS. The corresponding areas under the ROC curves (AUCs) of the nomogram at 3, 4 and 5 years in the training and validation set were 0.770, 0.788, 0.805, 0.778, 0.797, and 0.802, respectively. The calibration curves and DCA revealed that the prediction model had an excellent performance. Finally, the risk stratification system confirmed that the powerful role of the nomogram in distinguishing results and risk stratification.

Conclusion

Briefly, the nomogram incorporating various clinicopathological indicators was established for MCB patients and may facilitate clinical decision-making.

Using Ultrasound-Based Multilayer Perceptron to Differentiate Early Breast Mucinous Cancer and its Subtypes From Fibroadenoma

Objectives

Mucinous breast cancer (MBC), particularly pure MBC (pMBC), often tend to be confused with fibroadenoma (FA) due to their similar images and firm masses, so some MBC cases are misdiagnosed to be FA, which may cause poor prognosis. We analyzed the ultrasonic features and aimed to identify the ability of multilayer perceptron (MLP) to classify early MBC and its subtypes and FA.

Materials and Methods

The study consisted of 193 patients diagnosed with pMBC, mMBC, or FA. The area under curve (AUC) was calculated to assess the effectiveness of age and 10 ultrasound features in differentiating MBC from FA. We used the pairwise comparison to examine the differences among MBC subtypes (pure and mixed types) and FA. We utilized the MLP to differentiate MBC and its subtypes from FA.

Results

The nine features with AUCs over 0.5 were as follows: age, echo pattern, shape, orientation, margin, echo rim, vascularity distribution, vascularity grade, and tumor size. In subtype analysis, the significant differences were obtained in 10 variables (p-value range, 0.000–0.037) among pMBC, mMBC, and FA, except posterior feature. Through MLP, the AUCs of predicting MBC and FA were both 0.919; the AUCs of predicting pMBC, mMBC, and FA were 0.875, 0.767, and 0.927, respectively.

Conclusion

Our study found that the MLP models based on ultrasonic characteristics and age can well distinguish MBC and its subtypes from FA. It may provide a critical insight into MBC preoperative clinical management.

Oncotype DX 21-gene test has a low recurrence score in both pure and mixed mucinous breast carcinoma

The Oncotype DX 21-gene test can be used to predict chemotherapy efficacy in patients with estrogen receptor (ER)-positive and HER2-negative breast cancer; however, the data on the 21-gene recurrence score (RS) for mucinous breast carcinoma (MBC) are limited. The present study aimed to evaluate the distribution pattern and clinical value of the 21-gene RS in patients with MBC. A total of 38 pure MBC (PMBC) and 11 mixed MBC (MMBC) cases were retrospectively analyzed, and a total of 29 ER-positive and HER2-negative MBCs underwent the Oncotype DX 21-gene test. There were no statistically significant differences between the PMBCs and MMBCs in age, tumor size and molecular subtype; however, patients with MMBC showed a significantly higher incidence rate of nodal metastases compared with that in patients with PMBC (72.7 vs. 16.2%, respectively). Following surgery, 87.8 and 59.2% of the enrolled patients received endocrine therapy and chemotherapy, respectively. With a median follow-up of 65.6 months, the 5-year disease-free survival and overall survival rates were 97.0 and 100.0%, respectively. The 21-gene test revealed that the proportions of patients with MBC categorized into low (RS <18), intermediate (RS ≥18-30) and high (RS ≥30) risk groups were 51.7, 44.8 and 3.5%, respectively, and there was no statistically significant difference between the PMBC and MMBC cases. Notably, among the genes in the 21-gene RS testing, the expression levels of cathepsin V, progesterone receptor (PR) and CD68 were significantly higher in the PMBC group compared with that in the MMBC group. In conclusion, the current study demonstrated that patients with MBC had a favorable prognosis, and both PMBC and MMBC cases had a low- and intermediate-risk RS, which suggests that a considerable proportion of patients may be able to avoid chemotherapy. In addition, the high expression level of PR, based on the 21-gene test in PMBCs, indicated that they may have a more favorable response to endocrine therapy than MMBCs.

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.

Mucinous Breast Carcinoma: Clinicopathological Comparison With Invasive Ductal Carcinoma

Introduction

Invasive ductal carcinoma (IDC) is the most common histological subtype of breast cancer. Conversely, many special types of breast carcinoma were described with varying prognosis and hormone receptor status. Mucinous carcinoma (MC) is a rare special subtype of breast cancer, and only a few studies have evaluated the clinicopathological and hormone receptor profile of this type of breast cancer. Therefore, in this study, we compared the clinicopathological characteristics of MC with IDC in our population.

Methods

A retrospective observational study was conducted in the Department of Histopathology, Liaquat National Hospital and Medical College, from January 2013 till December 2020, for eight years. During this period, 38 cases of MC were diagnosed and 1268 cases of IDC were identified. All specimens were grossed according to standard protocols and representative sections were submitted from tumors, resection margins, and lymph nodes. Slides were examined by histopathologists to determine tumor type and grade. Immunohistochemical (IHC) stains were applied to evaluate estrogen receptor (ER), progesterone receptor (PR), Ki67, and human epidermal growth factor receptor 2 (HER2/neu) statuses.

Results

The mean age of the patients with MC was 56.47±13.90 years, and most of the patients were above 50 years of age. The mean tumor size was 34.89±19.70 mm. Most tumors were grade 1 (68.4%) with a low mean Ki67 index (15.21±14.06%). Axillary metastasis was present in 31.6% of cases and all of them were nodal (N)-stage N1. ER, PR, and HER2/neu positivity were noted in 94.7%, 78.9, and 10.5% cases, respectively. Compared with IDC, a significant association of MC was noted with age, Ki67 index, tumor (T)-stage, N-stage, and tumor grade. MC cases had a higher mean age than IDC cases. Comparative analysis revealed that MC had a lower frequency of axillary metastasis, a lower mean Ki67 index, and a lower tumor grade than IDC. About biomarker status, MC was noted to have a higher frequency of ER and PR expression, and a lower frequency of HER2/neu expression than IDC.

Conclusion

MC is a rare subtype of breast cancer. However, it is important to recognize this subtype of breast cancer as it is associated with a prognostically better pathological profile, such as lower tumor grade and Ki67 index, lower frequency of axillary metastasis, higher expression of ER and PR, and lower expression of HER2/neu.

Evaluation of efficacy of chemotherapy for mucinous carcinoma: a surveillance, epidemiology, and end results cohort study

Background

In this study, we investigated the impact of chemotherapy on breast cancer-specific survival (BCSS) in patients with mucinous carcinoma using the surveillance, epidemiology, and end results (SEER) database.

Methods

A large-scale SEER-based retrospective analysis was conducted; 13,329 patients with mucinous carcinoma from 1994 to 2014 were identified. Clinicopathological characteristics were compared using the chi-square test. BCSS curves were generated using the Kaplan-Meier method. The prognostic significance of all demographic and clinicopathological characteristics and treatment patterns were calculated using univariate and multivariate regression analyses.

Results

Mucinous carcinoma was demonstrated to be less aggressive than invasive ductal carcinoma and predicted a better prognosis in the Kaplan-Meier analysis (hazard ratios = 0.336, 95% confidence interval: 0.308-0.368, p < 0.001). Univariate and multivariate analyses revealed that chemotherapy did not provide any additional benefit for patients with mucinous carcinoma. Predictors for receiving chemotherapy were younger age, estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-positive status, higher grade, larger tumor size, lymph node involvement, radiation reception, and mastectomy. Further subgroup analysis verified that regardless of the hormone receptor (HR) and lymph node (LN) status, patients did not benefit from chemotherapy.

Conclusion

Our study showed that patients with HR+/LN- mucinous carcinoma did not benefit from chemotherapy and that chemotherapy could not improve the survival of all subtypes of mucinous carcinoma based on large-scale SEER data. These results support that patients with mucinous carcinoma could be exempt from chemotherapy. Additional research is needed to further evaluate the impact of adjuvant treatments, particularly in patients with favorable histology.

A Case of Pure Mucinous Breast Carcinoma in a 25-Year-Old Female Who Showed Complete Pathological Response to Neoadjuvant Chemotherapy despite Poor Clinical Response

Introduction

Mucinous breast carcinoma is a rare histologic subtype of primary breast cancers accounting for 1-6%. It is a rare histological variant in young patients and usually presents without lymph node involvement, and its pathological response to neoadjuvant chemotherapy is rarely reported.

Case Presentation

Pure mucinous breast carcinoma in a 25-year-old female was treated with neoadjuvant chemotherapy every 3 weeks for 8 cycles. After the fifth cycle, the mass size showed no change. We performed modified radical mastectomy in the left breast and axillary lymph node clearance. However, the pathological report showed a complete elimination of both the breast tumor and axillary lymph nodes, which were filled with mucus but did not contain malignant cells.

Discussion

Chemotherapy was profoundly effective against the tumor cells, but ineffective against large amounts of extracellular mucus. Even though the cancer cells were sensitive to chemotherapy, the volume of mucinous cancer couldnot be reduced.

Conclusion

In summary, the evaluation criteria of tumor response to chemotherapy based on maximum diameter only should be considered insufficient for mucinous carcinoma.

Epidemiology of Mucinous Adenocarcinomas

Simple Summary

Mucinous adenocarcinomas are a very uncommon type of cancer that is poorly studied. These cancers overexpress a jelly-like substance called mucin outside their cells. These cancers share characteristics to another group of cancers called signet ring cell adenocarcinomas, which express mucin inside their cells, and these cancers almost invariability have a worse outcome compared to conventional adenocarcinomas. In our study, we show that patient outcomes with mucinous adenocarcinomas depend largely on the site of the cancer, with both similarities and differences to cancers arising from signet ring cells. This work, along with our recent study on signet ring cell cancers, provides a solid epidemiological reference for future work to motivate investigations as to how recognizing this tumor histology should lead to more tailored cancer treatments in order to improve patient outcomes.

Abstract

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of adenocarcinomas where extracellular mucin comprises more than 50% of the tumor. Most literature on MAs relate to cancers from colorectal and breast sites; however, the literature lacks a standardized overview of the MA disease entity. Particularly in colorectal cancer, some MAs may have signet ring cells floating within the mucin, which may represent a highly metastatic phenotype. MAs and signet ring cell adenocarcinomas represent a spectrum of mucin-producing neoplastic conditions where in the latter most mucin is intracellular rather than extracellular. We recently published a standardized overview of signet ring cells, and in this companion work, using a retrospective cohort approach, we summarize the clinicodemographic and mortality outcomes of MAs in sixteen primary sites, comprising 95.6% of all MAs in the Surveillance, Epidemiology, and End Results Program (SEER), a population-level cancer database covering nearly one-third of the United States population. Compared to matching nonvariant adenocarcinomas, MAs have a slightly earlier age of onset with increased rates of regional and distant disease at presentation. Survival outcomes are highly dependent on tumor location, illustrating our poor understanding of MA tumor biology. The clinical significance of MA histology depends largely on tumor site.

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.

HER2-positive pure mucinous breast carcinoma: A case report and literature review

INTRODUCTION

Pure mucinous carcinoma is a rare type of breast carcinoma, but it usually has a favorable prognosis. Tumors of pure mucinous carcinoma are typically positive for both estrogen receptor (ER) and progesterone receptor (PR), and they do not commonly overexpress human epidermal growth factor receptor 2 (HER2). However, when tumors have HER2 overexpression and are progesterone receptor negative, the prognosis is worse.

PATIENT CONCERNS

A 59-year-old female reported a slow growth mass of 3 years, which was radiologically diagnosed as fibroadenoma at another institution. The patient came to our institution for treatment and follow-up. She had no salient past history.

DIAGNOSIS

Excisional biopsy revealed a pure mucinous breast carcinoma that was ER (100%, moderate-strong intensity), PR(-), 5% Ki-67 (+), and HER2(3+) by immunohistochemistry. The HER2 gene was found to be amplified by fluorescence in situ hybridization (FISH). The clinical staging was T2N0M0, with pathological grade I, subtype luminal B.

INTERVENTIONS

After a modified radical mastectomy, she received four 21-day cycles of intravenous docetaxel (75 mg/m), intravenous cyclophosphamide (600 mg/m), and intravenous trastuzumab (8 mg/kg) (loading dose) on day 1 followed by 6 mg/kg every 3 weeks to complete a full year of treatment. She then received 2.5 mg of letrozole daily for 5 years.

OUTCOMES

After following up for 2 years, the patient's outcome was survival without recurrence. Cardiac ultrasounds were performed every 3 months and there was no change in the left ventricular ejection fraction (LEVF).

CONCLUSION

It is essential to correctly diagnose the ER(+), PR(-) HER2(+) subtype in mucinous carcinoma. This type should be treated with chemotherapy and anti-HER2 therapy, as well as aromatase inhibitor endocrine therapy.

Combining the Ultrasound Features of Primary Tumor and Axillary Lymph Nodes Can Reduce False-Negative Rate during the Prediction of High Axillary Node Burden in BI-RADS Category 4 or 5 Breast Cancer Lesions

The purpose of this study was to determine whether incorporation of the ultrasound (US) features of the primary tumor and axillary lymph node (ALN) could improve the prediction of high axillary nodal burden (HNB) and, thus, avoid unnecessary sentinel lymph node biopsy (SLNB). A total of 347 patients with Breast Imaging Reporting and Data System US category 4 or 5 breast cancer lesions were included. Their pre-operative US features and post-operative pathologic results were collected. The patients were then divided into the following groups based on surgical histology: limited nodal burden (LNB: 0-2 LNs involved) and heavy nodal burden (HNB: ≥3 metastatic LNs). Univariate and multivariate logistic regression analyses were conducted to determine the most valuable variables for HNB prediction. Receiver operating characteristic curves were obtained to assess their values. We found that a non-circumscribed margin, cortical thickness (≥3 mm) and number (≥3) of suspicious ALNs are indicators for HNB prediction. The false-negative rate (FNR) in model 1 (cortical thickness + number of suspicious ALNs) was 15.5% versus 3.4% in model 2 (non-circumscribed margin + cortical thickness + number of suspicious ALNs). Our results indicate that combining the US features of the primary tumor and ALNs can reduce the FNR during HNB prediction.

The Genomic Landscape of Mucinous Breast Cancer

Mucinous carcinoma of the breast (MCB) is a rare histologic form of estrogen receptor (ER)-positive/HER2-negative breast cancer (BC) characterized by tumor cells floating in lakes of mucin. We assessed the genomic landscape of 32 MCBs by whole-exome sequencing and/or RNA-sequencing. GATA3 (23.8%), KMT2C (19.0%), and MAP3K1 (14.3%) were the most frequently mutated genes in pure MCBs. In addition, two recurrent but not pathognomonic fusion genes, OAZ1-CSNK1G2 and RFC4-LPP, were detected in 3/31 (9.7%) and 2/31 (6.5%) samples, respectively. Compared with ER-positive/HER2-negative common forms of BC, MCBs displayed lower PIK3CA and TP53 mutation rates and fewer concurrent 1q gains and 16q losses. Clonal decomposition analysis of the mucinous and ductal components independently microdissected from five mixed MCBs revealed that they are clonally related and evolve following clonal selection or parallel evolution. Our findings indicate that MCB represents a genetically distinct ER-positive/HER2-negative form of BC.

Breast-conserving therapy shows better prognosis in mucinous breast carcinoma compared with mastectomy: A SEER population-based study

Background

Mucinous breast carcinoma (MBC) is a relatively rare pathological type of breast cancer. Compared with mastectomy in MBC, the effect and safety of breast‐conserving therapy (BCT) remains unclear. Therefore, we investigated the long‐term prognosis of BCT and mastectomy in T1‐2 stage mucinous breast carcinoma via the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

Totally, 8830 patients who were diagnosed of mucinous breast carcinoma between 2004 and 2014 from SEER database were reviewed retrospectively. Cox proportional hazards model and Kaplan‐Meier method were performed for evaluating the relationship between surgical method and prognosis.

Results

One thousand three hundred and twenty (14.9%) patients underwent mastectomy and 7510 (85.1%) underwent BCT. The median follow‐up time was 77 months. There were more non‐Hispanic white, married, and younger (<65 years) patients, as well as lower stage of tumor sizes, lymph nodes and more favorable histologic grade, ER positive, and PR positive in BCT group (P < .05). Patients in BCT group had relatively better overall survival (OS) than those in mastectomy group. The risk of death from any cause in BCT group was lower than that in mastectomy group significantly (HR = 0.786, 95% CI: 0.703‐0.879, P < .001), while no difference significantly was observed in breast cancer‐specific survival (BCSS) between BCT and mastectomy groups. In stratified analysis according to T stage, BCT group had better OS than mastectomy group for patients of T1 stage (HR = 0.679, 95% CI: 0.589‐0.781, P < .001) or T2 stage (HR = 0.769, 95% CI: 0.646‐0.915, P = .003). In stratified analysis according to the different ages, BCT showed OS benefit in patients at the age of 50‐64 years (HR = 0.587, 95% CI: 0.408‐0.846, P = .004) and the age of 65‐79 years (HR = 0.636, 95% CI: 0.535‐0.758, P = .001). For patients younger than 50 years or not younger than 80 years, there was no difference significantly observed in OS between BCT and mastectomy groups (P > .05).While for patients who received BCT, the use of radiotherapy showed OS benefit.

Conclusions

This large population‐based study indicated patients who received BCT had better prognosis than those received mastectomy in T1‐2 stage MBC, especially in patients at the age of 50‐79 years. The use of radiotherapy showed OS benefit in patients receiving BCT. Breast‐conserving therapy might be preferred over mastectomy especially in locoregional treatment of T1‐2 stage MBC.

Omission of Chemotherapy for the Treatment of Mucinous Breast Cancer: A Nationwide Study from the Korean Breast Cancer Society

PURPOSE

Mucinous breast carcinoma (MBC) is a rare type of breast cancer. Although patients with MBC may have a better prognosis than that of patients with invasive ductal carcinoma, many clinicians administer adjuvant chemotherapy regimens similar to those for other breast tumors. Using data from a nationwide clinical database, this study evaluated the significance of adjuvant systemic chemotherapy and whether it can be omitted in MBC patients.

METHODS

We included 3,076 patients with a diagnosis of MBC recorded in the Korean Breast Cancer Registry between January 1990 and August 2016. We used the Kaplan-Meier method to analyze breast cancer-specific survival (BCCS) and overall survival (OS). Multivariate analysis was performed using a Cox proportional hazard ratio (HR) model to estimate the adjusted HR for each prognostic factor.

RESULTS

A total of 2,988 MBC patients were enrolled and followed-up for a median of 100 months (range, 2-324 months). Multivariate analysis revealed that axillary lymph node (ALN) metastasis and estrogen receptor (ER) negativity were significant prognostic factors for BCSS. Meanwhile, old age, pathologic tumor stage, and ALN metastasis were significant prognostic factors for OS. Subgroup analysis of ER-positive MBC showed that ALN metastasis was a significant prognostic factor for BCSS. Additionally, old age, pathologic tumor stage, and ALN metastasis were prognostic factors for OS. Ultimately, ALN metastasis was the most statistically significant prognostic factor for MBC. However, chemotherapy had no significant effect on BCSS and OS. The Kaplan-Meier curves of BCSS and OS based on pathologic tumor and nodal stages and age revealed that chemotherapy did not statistically significantly improve prognosis, except for the N3 stage.

CONCLUSION

Our large retrospective analysis revealed that adjuvant chemotherapy provided little benefit to improve the prognosis of most ER-positive MBC patients. Therefore, chemotherapy can be omitted in the treatment of most ER-positive MBC.

Mucinous breast cancer: A narrative review of the literature and a retrospective tertiary single-centre analysis

Mucinous carcinoma (MC) is a rare breast cancer characterized by the presence of large extracellular mucin amount. Two main subtypes can be distinguished: pure (PMC) and mixed (MMC). We conducted a retrospective MC analysis in our prospective maintained database, calculating disease-free survival (DFS) and 5-year overall survival (OS). We found a global 92.1% OS (higher in MMC group and statistically significative) and a DFS of 95.3% (higher in MMC group but not statistically significative).

Comparison of Clinical Features and Treatment Results of Mix Mucinous Carcinomas and Other Atypical Carcinomas of the Breast

OBJECTIVE

There are multiple subtypes of breast cancer with different biological and pathological features and accordingly exhibit different clinical behaviors. The aim of this study was to compare the treatment modalities, clinical features and prognostic characteristics of Mix Mucinous Carcinomas (MMBC) and other rare tumors of the breast.

MATERIALS AND METHOD

A total of 2152 patients who were operated on for breast cancer in our clinic between 2010-2019, with pathological diagnoses of tubular, pure mucinous, mix mucinous or papillary carcinoma were enrolled in the study. Patients were divided into two groups as mix mucinous patients (Group1) and other rare tumors (Group2). The demographic, clinical and prognostic characteristics and treatment approaches were compared between Groups, and additionally between the subtypes of Group 2.

RESULTS

42 patients participated in our study. Group 1 consisted of 7 patients, and Group2 consisted of 35 patients. The subtypes in Group2 were papillary (n=21), pure mucinous (n=10) and tubular (n=4). Progesterone Receptor Positivity was found to be significantly higher in Group 2 patients than in Group1 patients (p=0.005, p<0.05). Multicentricity rates in the tumors of the patients in Group1 were found to be statistically significantly higher than the patients in Group 2 (p=0.024, p<0.05). In subtype analysis in Group2, there were no statistically significant differences parameters in the subgroups (p>0.05). Mean survival was 19.5+5.6 (8.5-30.5) months in Group 1 and 46.3+5.2 (36.1-56.6) months, in Group2 when evaluated separately (p:0.002).

CONCLUSION

The prognosis of pure mucinosis (PMBC) and other atypical cancers of the breast compared to the (MMBC) is quite good. Rare pathological types of breast cancer can have favorable outcomes when treated with necessary oncological principles.

Imaging features of pure mucinous breast carcinoma: correlation with extracellular mucus content

AIM

To analyse the correlation between imaging features using multiple techniques and extracellular mucus content in pure mucinous breast carcinoma (PMBC).

MATERIALS AND METHODS

A retrospective review of available images from 25 patients with 25 PMBC tumours was conducted, with ultrasonography (US), ultrasonic elastography (USE), mammography, and breast-specific gamma imaging (BSGI) available for 25, 15, 11, and eight patients, respectively. Microscopic slides from each tumour were evaluated for extracellular mucus content. The correlation between imaging features and mucus content was analysed using linear-by-linear association chi-square tests or Spearman's rank correlation analyses.

RESULTS

On US images, a significant correlation was found between mucus content and echo pattern (p=0.042) and colour Doppler blood flow (p=0.032), with a trend that the lower mucus content present in tumours, the more likely they were detected with isoechoic echo and high blood flow. On USE images, a moderate negative correlation (r=-0.60, p=0.029) was observed between mucus content and tumour stiffness. On BSGI images, a strong negative correlation (r=-0.92, p=0.001) was shown between mucus content and lesion to non-lesion ratio (L/N) values of radioactivity counts. No significant correlation was found between mucus content and mammography imaging features (all p>0.05).

CONCLUSION

Imaging features at US, USE, and BSGI correlated with extracellular mucus content in PMBC tumours, among which the L/N value using BSGI imaging is the most relevant feature.

Huge mucinous carcinoma of the breast in which doubling time was observed by computed tomography during 3 years without treatment

Here we report the case of a 77-year-old woman with a huge cancer of the right breast for which size was measured on computed tomography in our hospital preoperatively and in other hospital 3 years earlier. During the 3-year untreated interval, the tumor grew from 4 cm to 13 cm in maximum diameter, and the tumor-volume doubling time (TVDT) was calculated as 209 days. The patient underwent mastectomy with axillary lymph node dissection, with the large skin defect covered by autologous skin graft. The pathological diagnosis was pure mucinous carcinoma (MC) of the breast with a low MIB-1 index, no vessel invasion, and no lymph node metastasis. Breast MC has been known to show a slow growth rate, but the TVDT of this current tumor was not markedly different from that of common breast cancers described in previous reports. This short TVDT notwithstanding the low aggressiveness may be due to abundant mucin occupying the majority of the tumor volume. To the best of our knowledge, no previous reports have provided accurate TVDTs for breast MC.

Tubular and mucinous breast cancer: results of a cohort of 917 patients

Objectives:

To analyze axillary lymph node involvement (ALNI) rate and survival for mucinous (MC) and tubular (TC) breast carcinomas considered being of very good prognosis and for which an axillary surgical exploration could be questioned.

Methods:

Our multicentric cohort consisted of 21,135 patients with clinically node-negative invasive breast cancer, without neoadjuvant therapy, between 1999 and 2013 in 10 French centers. ALNI rate and survival were analyzed according to patient and tumor characteristics.

Results:

Our cohort consisted of 672 TC and 245 MC. Patients were older and tumor size greater for MC and pathologic factors were more pejorative. The rate of mastectomies and adjuvant chemotherapy was higher in the MC group. Axillary lymph node status was determined by SLNB alone in 71.2% of patients. ALNI rates were 17.9% and 18% for TC and MC, respectively. ALNI rate was lesser for MC (OR 0.503, p = 0.024) and greater in case of lympho-vascular invasion (OR 5.0, p < 0.0001) and for tumors >10 mm (OR 2.17, p = 0.042). Median follow-up was 58 months. The 5- and 7-year overall survival rates were 97.1% and 95% for TC, respectively; 92.3% and 91.2% for MC ( p = 0.043); 5- and 7-year disease-free survival rates were 97.9% and 97.2% versus 95.2 and 93.6% ( p = 0.041). Lympho-vascular invasion was the only predictive factor for overall survival (hazard ratio [HR] = 2.70)’ grade 2 (HR = 10) and HR-negative (HR = 4.9) were the two predictive factors for disease-free survival.

Conclusion:

This study confirms the need for an axillary exploration for these tumors even for a tumor size <10 mm and a favorable prognosis.

Pure mucinous breast carcinoma in a 25-year-old female, a case report

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Young patient.

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Mucinous carcinoma.

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Prognosis.

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Hormone receptor.

Introduction

Mucinous carcinoma is a variant of invasive breast carcinomas representing 2% of them. These tumors frequently develop in postmenopausal females; it is a rare histological variant in young patients.

Case presentation

A 25-year-old female refers a slow growth mass of 2 years of evolution. Excisional biopsy reveals a pure mucinous carcinoma with positive hormone receptors and negative HER2. She was treated with hormone therapy and surgical resection.

Discussion

Mucinous carcinoma is a rare variant reported in young patients. Many series report that is frequently found in postmenopausal patients. We present a case of a pure mucinous carcinoma in a 25-year-old female with the importance of being a low-frequency malignancy in young patients.

Conclusion

Due to its benign course, it is important to know that this lesion can also present in young patients. The importance underlies in the multidisciplinary management at the right time in a proper way.

Whole-lesion histogram analysis of the apparent diffusion coefficient: Evaluation of the correlation with subtypes of mucinous breast carcinoma

PURPOSE

To evaluate the utility of the whole-lesion histogram apparent diffusion coefficient (ADC) for characterizing the heterogeneity of mucinous breast carcinoma (MBC) and to determine which ADC metrics may help to best differentiate subtypes of MBC.

MATERIALS AND METHODS

This retrospective study involved 52 MBC patients, including 37 pure MBC (PMBC) and 15 mixed MBC (MMBC). The PMBC patients were subtyped into PMBC-A (20 cases) and PMBC-B (17 cases) groups. All patients underwent preoperative diffusion-weighted imaging (DWI) at 1.5T and the whole-lesion ADC assessments were generated. Histogram-derived ADC parameters were compared between PMBC vs. MMBC and PMBC-A vs. PMBC-B, and receiver operating characteristic (ROC) curve analysis was used to determine optimal histogram parameters for differentiating these groups.

RESULTS

The PMBC group exhibited significantly higher ADC values for the mean (P = 0.004), 25^th (P = 0.004), 50^th (P = 0.004), 75^th (P = 0.006), and 90^th percentiles (P = 0.013) and skewness (P = 0.021) than did the MMBC group. The 25^th percentile of ADC values achieved the highest area under the curve (AUC) (0.792), with a cutoff value of 1.345 × 10^-3 mm² /s, in distinguishing PMBC and MMBC. The PMBC-A group showed significantly higher ADC values for the mean (P = 0.049), 25^th (P = 0.015), and 50^th (P = 0.026) percentiles and skewness (P = 0.004) than did the PMBC-B group. The 25^th percentile of the ADC cutoff value (1.476 × 10^-3 mm² /s) demonstrated the best AUC (0.837) among the ADC values for distinguishing PMBC-A and PMBC-B.

CONCLUSION

Whole-lesion ADC histogram analysis enables comprehensive evaluation of an MBC in its entirety and differentiating subtypes of MBC. Thus, it may be a helpful and supportive tool for conventional MRI.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:391-400.

Clinical Nomogram for Predicting Survival Outcomes in Early Mucinous Breast Cancer

Background

The features related to the prognosis of patients with mucinous breast cancer (MBC) remain controversial. We aimed to explore the prognostic factors of MBC and develop a nomogram for predicting survival outcomes.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was searched to identify 139611 women with resectable breast cancer from 1990 to 2007. Survival curves were generated using Kaplan-Meier methods. The 5-year and 10-year cancer-specific survival (CSS) rates were calculated using the Life-Table method. Based on Cox models, a nomogram was constructed to predict the probabilities of CSS for an individual patient. The competing risk regression model was used to analyse the specific survival of patients with MBC.

Results

There were 136569 (97.82%) infiltrative ductal cancer (IDC) patients and 3042 (2.18%) MBC patients. Patients with MBC had less lymph node involvement, a higher frequency of well-differentiated lesions, and more estrogen receptor (ER)-positive tumors. Patients with MBC had significantly higher 5 and10-year CSS rates (98.23 and 96.03%, respectively) than patients with IDC (91.44 and 85.48%, respectively). Univariate and multivariate analyses showed that MBC was an independent factor for better prognosis. As for patients with MBC, the event of death caused by another disease exceeded the event of death caused by breast cancer. A competing risk regression model further showed that lymph node involvement, poorly differentiated grade and advanced T-classification were independent factors of poor prognosis in patients with MBC. The Nomogram can accurately predict CSS with a high C-index (0.816). Risk scores developed from the nomogram can more accurately predict the prognosis of patients with MBC (C-index = 0.789) than the traditional TNM system (C-index = 0.704, P< 0.001).

Conclusions

Patients with MBC have a better prognosis than patients with IDC. Nomograms could help clinicians make more informed decisions in clinical practice. The competing risk regression model, as a more rational model, is recommended for use in the survival analysis of patients with MBC in the future.