MR imaging of mucinous carcinoma of the breast

Advanced magnetic resonance imaging of mixed mucinous breast cancer: A case report

Well-differentiated adenocarcinoma, a rare subtype of infiltrating ductal carcinoma, is a kind of mucinous cancer of the breast. It accounts for around 2% of all invasive breast cancers. The average age of presentation is 65-70 years, whereas women under the age of 35 account for 1% of cases. They are classified as pure or mixed carcinomas depending on the amount of mucin they include; knowing the difference is crucial for prognosis and therapy. Despite the lack of sufficient proof, the primary therapy for breast cancer is still surgery. Special forms of breast cancer are still being treated, although this is still a contentious topic. In this article, we intended to present a case of a mixed mucinous carcinoma in a 52-year-old female who was assessed by advanced magnetic resonance imaging.

Magnetic resonance imaging correlation with molecular and epigenetic markers in assessment of breast cancer

Background

Breast cancer is a heterogeneous disease with a wide range of clinical behavior, histologic subtypes, therapeutic options, and outcomes. The different biology and histology of breast cancer display different tumor morphology at breast magnetic resonance imaging (MRI). However, few studies have examined the relationship between the MRI morphological, kinetic features and molecular and epigenetic markers in breast cancer assessment. The study aimed to evaluate the correlation between MRI morphological and kinetic features, molecular and an epigenetic marker (linc-ITGB1) in breast cancer cases. A total of 115 women (80 cases and 35 controls) with BIRAD 4 category breast lesions were included. The association between the MRI morphological & kinetic features, apparent diffusion coefficient (ADC) values, and molecular and the epigenetic marker (linc-ITGB1) was evaluated using Mann–Whitney and Chi-square tests.

Results

The shape (p = 0.009), size of the lesion (p = 0.003), and pattern of enhancement (p ≤ 0.001) were significantly correlated with the molecular markers. Luminal subtypes are more likely to be presented with irregular shaped and non-circumscribed margin masses (97% for luminal A and 94.1% for luminal B). Triple-negative cancers are frequently presented with regular masses, circumscribed margins, and peripheral rim enhancement (50% of TN tumors). HER2-positive cancers are more likely to be multifocal/multicentric and are more associated with non-mass pattern of enhancement as compared to HER2-negative cancers. Perilesional edema was also significantly correlated with HER2-positive lesions (p = 0.009). Although the epigenetic marker linc-ITGB1 was overexpressed by 4.85-folds in breast cancer cases compared to benign controls, we could not find any significant correlation between its expression level and the MRI features or molecular subtypes (p = 0.948).

Conclusions

MRI features can be a reliable predictor of breast cancer molecular subtypes. The epigenetic marker linc-ITGB1 has a potential role in breast cancer pathogenesis but with no significant correlation with either the MRI features or molecular subtypes of the lesions.

Triple-negative breast cancer on contrast-enhanced MRI and synthetic MRI: A comparison with non-triple-negative breast carcinoma

PURPOSE

This study aimed to compare the characteristics of triple-negative breast cancer (TNBC) with non-TNBC on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and synthetic MRI.

METHOD

This retrospective study included 79 patients with histopathologically proven breast cancer (TNBC: 16, non-TNBC: 63) who underwent synthetic MRI. Using synthetic MR images, we obtained T1 and T2 relaxation times in breast lesions before (Pre-T1, Pre-T2, Pre-PD) and after (Gd-T1, Gd-T2, Gd-PD) contrast agent injection. Subsequently, we calculated the ΔT1 (Pre-T1 - Gd-T1), ΔT2 (Pre-T2 - Gd-T2), Pre-T1/T2, and Gd-T1/T2. We compared the aforementioned quantitative values, as well as several morphologic features between TNBCs and non-TNBCs that were identified on DCE-MRI.

RESULTS

The multivariate analyses revealed that the Pre-T2 (P = 0.037) and the presence of rim enhancement (P-RIM) (P = 0.034) were significant and independent predictors of TNBC. The area under the receiver operating characteristics curve for all breast cancers was greater when a combination of Pre-T2 and P-RIM (Pre-T2＋P-RIM; Method 3, AUC (area under the curve) = 0.858) was used to distinguish between TNBCs and non-TNBCs versus the use of either Pre-T2 alone (Method 1, AUC = 0.786) or P-RIM alone (Method 2, AUC = 0.747).

CONCLUSIONS

Pre-T2 obtained using synthetic MRI and P-RIM identified on DCE-MRI allowed the differentiation between TNBCs and non-TNBCs. However, these results are preliminary and need to be verified by further studies.

Estimation of T2* Relaxation Time of Breast Cancer: Correlation with Clinical, Imaging and Pathological Features

OBJECTIVE

The purpose of this study was to estimate the T2* relaxation time in breast cancer, and to evaluate the association between the T2* value with clinical-imaging-pathological features of breast cancer.

MATERIALS AND METHODS

Between January 2011 and July 2013, 107 consecutive women with 107 breast cancers underwent multi-echo T2*-weighted imaging on a 3T clinical magnetic resonance imaging system. The Student's t test and one-way analysis of variance were used to compare the T2* values of cancer for different groups, based on the clinical-imaging-pathological features. In addition, multiple linear regression analysis was performed to find independent predictive factors associated with the T2* values.

RESULTS

Of the 107 breast cancers, 92 were invasive and 15 were ductal carcinoma in situ (DCIS). The mean T2* value of invasive cancers was significantly longer than that of DCIS (p = 0.029). Signal intensity on T2-weighted imaging (T2WI) and histologic grade of invasive breast cancers showed significant correlation with T2* relaxation time in univariate and multivariate analysis. Breast cancer groups with higher signal intensity on T2WI showed longer T2* relaxation time (p = 0.005). Cancer groups with higher histologic grade showed longer T2* relaxation time (p = 0.017).

CONCLUSION

The T2* value is significantly longer in invasive cancer than in DCIS. In invasive cancers, T2* relaxation time is significantly longer in higher histologic grades and high signal intensity on T2WI. Based on these preliminary data, quantitative T2* mapping has the potential to be useful in the characterization of breast cancer.

Magnetic resonance imaging and pathological characteristics of pure mucinous carcinoma in the breast according to echogenicity on ultrasonography

Purpose

The aim of this study was to explore the clinical and pathological characteristics of pure mucinous breast carcinoma (PMBC) according to internal echogenicity on ultrasonography (US).

Methods

Thirty-three patients with PMBC diagnosed at surgery were included in this study. Cases of PMBC were classified according to internal echogenicity on US. The imaging features on magnetic resonance (MR) imaging and clinicohistopathological characteristics were compared between the hypoechogenic and the isoechogenic to hyperechogenic groups.

Results

Eleven cases of PMBC (33.3%) exhibited hypoechogenicity on US, while 22 cases (66.7%) exhibited isoechogenicity or hyperechogenicity. Of the isoechogenic to hyperechogenic PMBCs, 95.5% showed a high signal on T2-weighted images, which was a significantly greater percentage than was observed for the hypoechogenic group (54.5%) (P=0.010). Of the hypoechogenic PMBCs, 63.6% showed a washout pattern in the delayed phase, which was substantially more than the result of 23.8% observed for the isoechogenic to hyperechogenic PMBCs (P=0.053).

Conclusion

PMBCs with isoechogenicity or hyperechogenicity were more likely to show a high signal intensity on T2-weighted images than hypoechogenic PMBCs. However, other MR imaging and clinicohistopathological characteristics were not significantly different between the two groups.

Apparent diffusion coefficient in differentiation between malignant and benign breast masses: does size matter?

AIM

To determine whether lesion size affects the diagnostic performance of apparent diffusion coefficient (ADC) in the evaluation of breast masses.

MATERIALS AND METHODS

Consecutive breast lesions detected at magnetic resonance imaging (MRI) from June 2010 to July 2013 were retrospectively reviewed. Differences in the ADCs of benign and malignant mass lesions were compared. Receiver operating characteristics analysis was performed to evaluate diagnostic performance of ADC regarding lesion size (≤ 1 cm or >1 cm) and their T2W signal intensities.

RESULTS

Seventy-four malignant lesions (77.9%) and 21 (22.1%) benign lesions were included. Twenty-two of the 95 (23.2%) masses measured ≤ 1 cm (mean 0.73 ± 0.4; range 0.51-0.8 cm) and 73/95 (76.9%) masses measured >1 cm (mean 2.11 ± 0.1; range 1.1-3.3 cm). The mean ADC was significantly lower for malignant than for benign lesions (mean for malignant lesion, 0.89 ± 0.29 × 10(-3) mm(2)/s; mean for benign lesions, 1.27 ± 0.42 × 10(-3) mm(2)/s; p<0.01). The optimal ADC cut-off for differentiating benign and malignant lesion was 1.088 × 10(-3) mm(2)/s with a sensitivity of 85.9% and specificity of 77% for lesions >1 cm. The sensitivity and specificity were lowered to 60% and 50%, respectively, for lesions of size ≤ 1. Maximal sensitivity and specificity were reached when the ADC value was used to evaluate T2-dark lesions.

CONCLUSION

Diffusion-weighted MRI is useful for characterizing masses that are hypointense on T2-weighted images. Lower sensitivity and specificity were found for breast lesions ≤ 1 cm.

T 1 relaxation measurement of ex-vivo breast cancer tissues at ultralow magnetic fields

We investigated T 1 relaxations of ex-vivo cancer tissues at low magnetic fields in order to check the possibility of achieving a T 1 contrast higher than those obtained at high fields. The T 1 relaxations of fifteen pairs (normal and cancerous) of breast tissue samples were measured at three magnetic fields, 37, 62, and 122 μT, using our superconducting quantum interference device-based ultralow field nuclear magnetic resonance setup, optimally developed for ex-vivo tissue studies. A signal reconstruction based on Bayesian statistics for noise reduction was exploited to overcome the low signal-to-noise ratio. The ductal and lobular-type tissues did not exhibit meaningful T 1 contrast values between normal and cancerous tissues at the three different fields. On the other hand, an enhanced T 1 contrast was obtained for the mucinous cancer tissue.

Invasive mucinous carcinoma of the breast

Mucinous carcinoma of the breast is one of the rarer forms of intramammary cancer, often presenting as a lobulated, fairly well circumscribed mass on mammography, sonography, and gadolinium-enhanced magnetic resonance imaging. It accounts for 1% to 7% of all breast cancers and generally carries a better prognosis than other types of malignant breast cancers. Metastatic disease occurs at a lower frequency than in other types of invasive carcinoma. We present an atypical case of mucinous carcinoma in a woman who presented with a palpable intramammary lymph node metastasis from an unknown breast primary. Subsequent magnetic resonance imaging and percutaneous biopsy demonstrated histologic findings consistent with a mixed mucinous neoplasm with a micropapillary pattern.

Magnetic resonance in the detection of breast cancers of different histological types

Breast cancer incidence is increasing worldwide. Early detection is critical for long-term patient survival, as is monitoring responses to chemotherapy for management of the disease. Magnetic resonance imaging and spectroscopy (MRI/MRS) has gained in importance in the last decade for the diagnosis and monitoring of breast cancer therapy. The sensitivity of MRI/MRS for anatomical delineation is very high and the consensus is that MRI is more sensitive in detection than x-ray mammography. Advantages of MRS include delivery of biochemical information about tumor metabolism, which can potentially assist in the staging of cancers and monitoring responses to treatment. The roles of MRS and MRI in screening and monitoring responses to treatment of breast cancer are reviewed here. We rationalize how it is that different histological types of breast cancer are differentially detected and characterized by MR methods.

Primary breast amyloidosis presenting solely as nonpalpable microcalcifications: a case report with review of the literature

Primary breast amyloidosis is a rare disease and usually occurs as unilateral or bilateral palpable masses. Primary breast amyloidosis presenting solely as microcalcifications is extremely rare. The authors report a case of a 73-year-old woman with persistent suspicious microcalcifications without palpable mass. The diagnosis was established by the presence of an amorphous and eosinophilic material that was positive for Congo red and dichroic under polarized light. Paraffin immunohistochemistry revealed the presence of kappa light chains (AL-type amyloidosis). The amyloid deposits were associated with microcalcifications. A complete work up was performed to exclude other localisations or associated pathologies and was negative. The primary breast amyloidosis is discussed and a review of the literature is presented.

The necrosis sign in magnetic resonance-mammography: diagnostic accuracy in 1,084 histologically verified breast lesions

Necrosis sign (NS) is a new descriptor for differential diagnosis of breast lesions in magnetic resonance (MR)-mammography (MRM). This study was designed: (a) to analyze diagnostic accuracy of NS in 1,084 histologically verified breast lesions, (b) to assess performance of NS in subgroups. This study was approved by the local ethical committee. All histologically verified lesions having undergone MR-mammography at our institution over 12 years were evaluated by experienced radiologists (> 500 MRM) according to standard protocols and study design (T1w; 0.1 mmol/kg bw gadolinium diethylenetriamine penta-acetic acid; T2-turbo spin echo (TSE)). Patients with history of breast biopsy (surgically, minimal-invasive), radiation- or chemotherapy ≤ 1 year before MRM were excluded. NS was assessed on T2w-TSE sequences and was rated positive if a hyperintense center in a hypointense lesion could be visualized (chi-squared test). One thousand and eighty-four lesions were available for statistical analysis (648: malignant, 436: benign). NS was significantly associated with malignancy (p < 0.001), providing specificity and positive predictive value (PPV) of 96.1% and 78.8%. Malignant lesions > 20 mm presented significantly more often NS (p < 0.001) than neoplasias ≤ 20 mm. There was no difference regarding prevalence of NS in small versus advanced benign lesions (n.s.), leading to better performance of NS in lesions > 20 mm (PPV: 87.8%). Correlation between NS and Grading of invasive carcinomas was significant. In this study of 1,084 lesions necrosis sign was a specific and highly predictive feature for differential diagnosis in MRM (Specificity: 96.1%; PPV: 78.8%). This particularly counts for advanced lesions (PPV 87.8%). As this new descriptor correlates with Grading, it could be used as an initial estimate of patient's prognosis.

Radiologic and pathologic findings in breast tumors with high signal intensity on T2-weighted MR images

Various histopathologic components in benign and malignant breast lesions may generate hyperintense signal at T2-weighted magnetic resonance (MR) imaging. A comparison of the specific histologic features found in breast lesions with a high-signal-intensity appearance on unenhanced T2-weighted turbo spin-echo MR images obtained without spectral fat suppression shows that this MR imaging characteristic is often suggestive of the differential diagnosis. Histopathologic features that may produce high signal intensity in breast lesions include extensive necrosis, a cystic or microcystic component, an adipose or sebaceous component, mucinous stroma, loose myxoid stroma, stromal edema, and hemorrhagic changes. A more nuanced understanding of the correlation between the MR imaging appearance and specific pathologic findings may help radiologists achieve earlier and more accurate differentiation among this group of breast lesions.

Assessment of breast lesions with diffusion-weighted MRI: comparing the use of different b values

OBJECTIVE

Our purpose was to study the utility of diffusion-weighted MRI in differentiating benign from malignant breast lesions by assessing the best b values.

SUBJECTS AND METHODS

Forty-five women (mean age, 46.1 years) with 52 focal mass breast lesions underwent diffusion-weighted imaging with different b values. The apparent diffusion coefficient (ADC) value of each lesion was calculated from the ADC maps done using five b values (0, 250, 500, 750, and 1,000 s/mm(2)) and using b values of 0 s/mm(2) with each other b value separately (0 and 250 s/mm(2), 0 and 500 s/mm(2), 0 and 750 s/mm(2), 0 and 1,000 s/mm(2)). The mean ADC values were correlated with imaging findings and histopathologic diagnoses. The cutoff ADC value, sensitivity, and specificity of diffusion-weighted imaging to differentiate benign and malignant lesions were calculated in all b value combinations. A p value of < 0.05 was considered statistically significant.

RESULTS

The mean ADC value was significantly lower for malignant lesions compared to benign lesions (p < 0.0001) in all b value combinations. No statistical difference was seen between the ADC obtained from different b value combinations (p = 0.2581) in the differentiation between benign and malignant lesions. The ADC calculated from b 0 and 750 s/mm(2) was slightly better than the other b value combinations, showing a sensitivity of 92.3% and a specificity of 96.2%.

CONCLUSION

Diffusion-weighted imaging is a potential resource as a coadjutant of MRI in the differentiation between benign and malignant lesions. Such imaging can be performed without a significant increase in examination time, especially because it can be done with lower b values.

MRI features of pancreatic colloid carcinoma

OBJECTIVE

The purpose of our study was to retrospectively investigate the MRI findings (diameter, location, contour and margin, signal intensity characteristics, and enhancement patterns) in a series of eight patients with pathologically proven colloid carcinoma of the pancreas.

CONCLUSION

Colloid carcinomas of the pancreas appear as masses with lobulating contours, indiscrete margins, and hyperintensity on T2-weighted images (n = 8). In addition, all patients who underwent dynamic studies (n = 4) showed peripheral and internal sponge-like or mesh-like progressive delayed contrast enhancement.

O uso da difusão por ressonância magnética na diferenciação das lesões mamárias benignas e malignas

OBJETIVO: Estudar a utilidade da sequência pesada em difusão na diferenciação das lesões mamárias benignas e malignas. MATERIAIS E MÉTODOS: Quarenta e cinco mulheres (idade média de 46,1 anos) com 52 nódulos de mama foram submetidas a ressonância magnética acrescida da sequência difusão. O coeficiente de difusão aparente (ADC) foi calculado através do mapa de ADC obtido pelo uso de cinco valores de b (0, 250, 500, 750 e 1.000 s/mm²). O valor de ADC médio de cada lesão foi correlacionado com achados de imagem e resultados histopatológicos. Valores de ADC de corte, sensibilidade e especificidade da sequência difusão na diferenciação das lesões benignas e malignas foram calculados. P < 0,05 foi considerado estatisticamente significativo. RESULTADOS: O valor de ADC médio foi significativamente menor para as lesões malignas (0,92 ± 0,26 × 10-3 mm²/s) comparado com as lesões benignas (1,50 ± 0,34 × 10-3 mm²/s) (p < 0,0001). A sequência difusão mostrou altas sensibilidade e especificidade (ambas 92,3%) na diferenciação entre lesões benignas e malignas. CONCLUSÃO: A sequência pesada em difusão representa um recurso potencial como coadjuvante da ressonância magnética das mamas na diferenciação das lesões benignas e malignas. Tal sequência pode ser facilmente inserida no protocolo padrão da ressonância magnética das mamas, sem aumento significativo no tempo de exame.

Typical atypical findings on dynamic MRI of the breast

Dynamic contrast enhanced magnetic resonance imaging (DCE MRI) of the breast has become an important tool to detect and characterize breast disease. The American College of Radiology Breast Imaging Reporting and Data System (BI-RADS(®)) provides a standardized vocabulary for describing the morphologic features and contrast kinetics of breast lesions. However, some lesions may show morphologic and dynamic MR features not consistent with their histologic nature resulting in incorrect categorization as malignant or benign. Another cause of diagnostic problems is artifacts. Thus correct interpretation of dynamic MRI of the breast demands knowledge of the most common pitfalls encountered in clinical practice. A pictorial overview of these is presented, with particular reference to the differentiation of malignant tumors from benign lesions.

Breast carcinoma--rare types: review of the literature

Invasive breast cancer is a heterogeneous disease in its presentation, pathological classification and clinical course. However, there are more than a dozen variants which are less common but still very well defined by the World Health Organization (WHO) classification. The rarity of many of these neoplasms does not allow large or randomized studies to define the optimal treatment. Many of the descriptions of these cancers are from case reports and small series. Our review brings updated information on 16 epithelial subtypes as classified by the WHO system with a very concise histopathology description and parameters helpful in the clinic. The aim of our review is to provide a tool for breast cancer caregivers which will enable a better understanding of the disease and its optimal approach to therapy. This may also stand as a clinical framework for a future understanding of these rarer breast cancers when gene analysis work is reported.

Triple-negative breast cancer: correlation between MR imaging and pathologic findings

PURPOSE

To retrospectively evaluate the magnetic resonance (MR) imaging findings of "triple-negative" breast cancer (ie, cancer that is estrogen receptor [ER] negative, progesterone receptor [PR] negative, and human epidermal growth factor receptor 2 [HER2] negative) and to compare them with those of breast cancers that are ER positive, PR positive, and HER2 negative.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. The MR imaging findings in 176 randomly assigned women (mean age, 56 years; range, 29-87 years) with surgically confirmed triple-negative breast cancers (n = 59) or ER-positive/PR-positive/HER2-negative breast cancers (n = 117) were reviewed. MR imaging findings included tumor shape, margin, internal enhancement, and size, as well as intratumoral signal intensity that was stronger than or almost the same as that of water or vessels on T2-weighted MR images. The MR imaging findings were compared with the pathologic findings.

RESULTS

High histologic grade (P < .001), unifocal lesion (P = .012), mass lesion type (P < .001), smooth mass margin (P = .001), rim enhancement (P < .001), persistent enhancement pattern (P = .005), and very high intratumoral signal intensity on T2-weighted MR images (P = .002) were significantly associated with triple-negative breast cancer. Very high intratumoral signal intensity on T2-weighted MR images was significantly associated with intratumoral necrosis (P < .001).

CONCLUSION

Several MR imaging features might be used for detecting triple-negative breast cancer.

A retrospective review with long term follow up of 11,400 cases of pure mucinous breast carcinoma

BACKGROUND

Pure mucinous breast carcinoma (PMBC) is a rare histologic type of mammary neoplasm. It has been associated with a better short-term prognosis than infiltrating ductal carcinoma (IDC) but identical long-term survival curves have been reported. The value of tumor size for TNM staging has been challenged because of the mucin content of the lesions. This study presents a large PMBC series with 20 years follow up as compared to IDC. The relative significance of a variety of common prognostic factors is calculated for this uncommon histology.

MATERIALS AND METHODS

A retrospective analysis of all PMBC cases reported in the SEER database between 1973 and 2002 was conducted. Overall survival (OS) and disease specific survival (DSS) were calculated at 5, 10, 15 and 20 years of follow up. Those curves were compared with all the IDC cases reported into the database during the same period. The prognostic significance of gender, race, laterality, age at diagnosis, T and N status, estrogen and progesterone receptors and administration of radiation therapy was calculated by univariate and multivariate analysis.

RESULTS

There were 11,422 PMBC patients reported. The median age at diagnosis was 71 years (Range 25-85). Fifty three percent of the tumors were well differentiated, 38% were moderately differentiated and the remaining 9% were poorly differentiated or anaplastic. The majority of the tumors were located in the upper outer quadrant (44%) the other 56% were roughly evenly divided between the upper inner, lower inner, lower outer and central quadrants. Eighty six percent of the patients had only localized disease at the time of surgery without nodal or distant disease while 12% had regional nodal involvement and 2% had distant metastases. The PMBC cases showed a better differentiation with lesions of lesser grade and more frequent ER/PR expression, smaller size and lesser nodal involvement when compared to the IDC cases of the same period. Kaplan Meier survival curves revealed a 5 years. breast cancer specific survival rate of 94%. Although slowly decreasing with time, 10, 15 and 20 years survival were 89%, 85% and 81% respectively compared to 82% (5 year), 72% (10 year), 66% (15 year) and 62% (20 year) for IDC. There were no significant differences in overall survival. Multivariate analysis by Cox regression revealed the nodal status (N) to be the most significant prognostic factor followed by age, tumor size (T), progesterone receptors and nuclear grade. Disease specific survival curves stratified for nodal status revealed a highly significant difference between node negative and node positive patients. The addition of radiation therapy after surgery did not significantly improve overall survival.

CONCLUSIONS

This large retrospective comparative analysis confirms the less aggressive behavior of PMBC compared to IDC. This favorable outcome is maintained after 20 years. This tumor presents typically in older patients and is rarely associated with nodal disease. Positive nodal status appears to be the most significant predictor of worse prognosis.

Apparent diffusion coefficients of breast tumors: clinical application

PURPOSE

To evaluate the usefulness of apparent diffusion coefficient (ADC) for the differential diagnosis of breast tumors and to determine the relation between ADC and tumor cellularity.

MATERIALS AND METHODS

One hundred and thirty-six female patients (age range, 17-83 years; average age, 51.7 years) with 140 histologically proven breast tumors underwent diffusion-weighted magnetic resonance (MR) imaging (DWI) using the spin-echo echo-planar technique, and the ADCs of the tumors were calculated using 3 different b values, 0, 500, and 1000 s/mm(2). The diagnoses consisted of fibroadenoma (FA, n=16), invasive ductal carcinoma, not otherwise specified (IDC, n=117), medullary carcinoma (ME, n=3) and mucinous carcinoma (MU, n=4). Tumor cellularity was calculated from surgical specimens. The ADCs of breast tumors and cellularity were compared between different histological types by analysis of variance and Scheffe's post hoc test. The correlation between tumor cellularity and ADC was analyzed by Pearson correlation test.

RESULTS

Significant differences were observed in ADCs between FA and all types of cancers (P<0.05) and between MU and other types of cancers (P<0.01) and in cellularity between FA and cancers except MU (P<0.01) and between MU and other types of cancers (P<0.01). There was an inverse correlation between ADC and tumor cellularity (P<0.01, r(2)=0.451).

CONCLUSIONS

The ADC may potentially help in differentiating benign and malignant breast tumors. Tumor ADC correlates inversely with tumor cellularity.

Rare breast neoplasms: is there any peculiar feature on magnetic resonance mammography?

PURPOSE

The purpose of this study is to describe the semiological features of rare breast neoplasms at magnetic resonance mammography (MRM).

MATERIALS AND METHODS

Out of 468 MRMs of patients with a histological diagnosis of breast malignancy, 27 (5.7%) cases of rare breast neoplasms, confirmed by definitive histological analysis on surgical specimens, were selected: four (0.9%) intracystic papillary neoplasms, four (0.9%) intraductal papillary neoplasms, five (1.0%) invasive papillary neoplasms, two (0.4%) medullary carcinomas, seven (1.5%) mucinous carcinomas, three (0.6%) tubular carcinomas, one (0.2%) tubulo-lobular carcinoma and one (0.2%) desmoid tumour. Two radiologists evaluated the MRM images according to Fischer criteria and indicated a level of diagnostic suspicion. In particular, MRM lesion morphology and enhancement characteristics were analysed.

RESULTS

No semiologic features of malignancy or peculiar appearances indicating rare breast neoplasm were identified. On the contrary, MRM appearance was nonspecific and often suggestive of probably benign (Breast Imaging Reporting and Data System-BI-RADS 3) (40%) or benign lesions (BI-RADS 2) (7.5%), or lesions were undetectable at MRM (BI-RADS 1) (7.5%).

CONCLUSIONS

Frequently, rare breast neoplasms show low suspicious morphologic and kinetic patterns at MRM, and they are often classified as indeterminate lesions. This is probably due to their high grade of differentiation and their histological features.

Diffusion weighted imaging in breast MRI: comparison of two different pulse sequences

RATIONALE AND OBJECTIVES

Comparison of two different diffusion weighted (DW) sequences in breast MRI regarding the differentiation between benign and malignant lesions.

MATERIALS AND METHODS

Breast MRI including two different DW sequences was performed in 165 consecutive women. Inclusion criteria for DW imaging and ADC evaluation were histologically proven focal mass lesions with a diameter of more than 5 mm in dynamic contrast-enhanced MRI. The DW sequences were pre-contrast echo-planar imaging with spectral fat saturation (EPI fs) and DW EPI with inversion recovery (EPI STIR) (b-values: 50, 400, and 800). Lesions were analyzed regarding visibility in DW sequences and ADC values.

RESULTS

Inclusion criteria were fulfilled in 56 women with 69 lesions. Five lesions could not be evaluated for different reasons. Finally, DW sequences were evaluated in 51 women with 64 focal mass lesions (15 benign, 49 malignant). The visibility of the lesions was significantly better in the EPI fs sequence (P<0.05). The ADC values (10(-3) mm(2)/s) in the EPI fs were 1.76, 2.58, and 1.21 (mean, maximum, minimum, respectively) for benign lesions and 0.90, 1.19, and 0.34 for malignant lesions. Respective values in the EPI STIR sequence were 1.92, 3.20, 1.10, and 0.91, 1.43, 0.35. Only in the EPI fs sequence there was no overlap in ADC values between benign and malignant lesions.

CONCLUSION

The DW MRI of the breast with EPI fs and EPI STIR sequences has a high potential to differentiate between benign and malignant breast lesions. Due to better lesion visibility and selectivity, the EPI fs sequence should be preferred.

A wide variety of dynamic contrast-enhanced MR appearances of breast cancer: pathologic correlation study

PURPOSE

The aim of this study was to elucidate the characteristic magnetic resonance (MR) appearance of breast cancers, as well as, its variations and to investigate the pathology providing different patterns of dynamic-MR appearances.

MATERIALS AND METHODS

Fifty-two women with cancer underwent mastectomy (52 tumors resected) and had MR imaging at our institution between April 2001 and March 2004. MR images of T1WI, T2WI, dynamic-MRI and contrast-enhanced T1WI were obtained and evaluated. Dynamic-MR images were correlated with pathological findings.

RESULTS

Common MR appearance of breast cancer was a focal mass either with irregular or spiculated margins with similar signal intensity on T1WI as and similar to higher signal intensity on T2WI compared to the normal mammary gland. On static contrast-enhanced T1WI, apparent enhancement was typically observed. On dynamic MRI, tumor-rim-enhancement on an early phase image and washout enhancement pattern on dynamic images, both characteristic for breast cancer, were observed, however, the prevalence of them was relatively low, which could be explained by the variation of histopathology among breast cancer nodules.

CONCLUSION

In diagnosing breast masses on MRI, as well as the common and characteristic findings of breast cancer, the variations of MR findings and their underlying histopathology should also be considered.

Atlas of breast magnetic resonance imaging

Magnetic resonance imaging (MRI) of the breast has become important not only for assessing the extent of breast cancer for breast-conserving surgery but also for the evaluation and diagnosis of other benign and malignant pathologies. We radiologists therefore need to know the appropriate indications for performing breast MRI and understand the MRI features of breast disease. We herein review and discuss the application of current pulse sequences and the imaging strategies for MRI of breast pathologies. We will illustrate the MRI features of various breast pathologies including malignant tumors such as invasive and noninvasive ductal carcinoma, special types of invasive carcinoma (mucinous, apocrine, lobular carcinoma, spindle cell carcinoma, and so on), inflammatory carcinoma, semimalignant tumor (phyllodes tumor), benign tumors (fibroadenoma, intraductal and intracystic papilloma), inflammatory conditions, and postsurgical changes. We will also demonstrate three-dimensional fusion images of MR ductography and breast MRI of patients with nipple discharge.

Diagnosis of breast tumors by contrast-enhanced MR imaging: comparison between the diagnostic performance of dynamic enhancement patterns and morphologic features

PURPOSE

To compare the diagnostic performance of breast lesions by the enhancement patterns and morphologic criteria on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Both T1-weighted 3D gradient-echo sequences with high temporal resolution and high-spatial-resolution MRI were performed on 190 patients with a total of 204 enhancing lesions (144 malignant and 60 benign). The enhancement patterns and morphologic features of each mass and nonmass lesion were analyzed, and the diagnostic performance was compared.

RESULTS

The sensitivity and specificity of the morphologic criteria were statistically significantly higher than those of the enhancement patterns (sensitivity: P = 0.0012, specificity: P = 0.0003), and the A(z) values for the three observers were 0.900, 0.919, and 0.900. The diagnostic accuracy of the morphologic criteria for both types of lesions was superior, and the differences were statistically significant (mass: P = 0.0001, nonmass: P = 0.0389).

CONCLUSION

The analysis of the morphologic features of enhancing breast lesions alone showed higher diagnostic performance; therefore, signal intensity (SI) time-course data may not be needed to diagnose malignant breast lesions.

Unusual Breast Cancers: Useful Clues to Expanding the Differential Diagnosis

Invasive ductal carcinoma and ductal carcinoma in situ account for about 85% of breast cancers. Unusual breast neoplasms may be broadly divided into invasive lobular carcinoma, well-differentiated subtypes of invasive ductal carcinoma, cancers of stromal origin, and metastatic neoplasms. Clues are often present in imaging characteristics, patient demographics, and/or clinical features that may suggest that the finding is not the usual type of breast cancer. Some rare malignancies also provide specific clues to their diagnosis. This review provides an overview of unusual and a few rare malignant breast neoplasms, highlighting particular or specific clinical or imaging findings that will enable residents to expand their differential diagnosis of breast lesions beyond invasive ductal carcinoma.

Magnetic resonance mammography in the evaluation of recurrence at the prior lumpectomy site after conservative surgery and radiotherapy

INTRODUCTION

The aim was to assess the value of magnetic resonance mammography (MRM) in the detection of recurrent breast cancer on the prior lumpectomy site in patients with previous conservative surgery and radiotherapy.

METHODS

Between April 1999 and July 2003, 93 consecutive patients with breast cancer treated with conservative surgery and radiotherapy underwent MRM, when a malignant lesion on the site of lumpectomy was suspected by ultrasound and/or mammography. MRM scans were evaluated by morphological and dynamic characteristics. MRM diagnosis was compared with histology or with a 36-month imaging follow-up. Enhancing areas independent of the prior lumpectomy site, incidentally detected during the MRM, were also evaluated.

RESULTS

MRM findings were compared with histology in 29 patients and with a 36-month follow-up in 64 patients. MRM showed 90% sensitivity, 91.6% specificity, 56.3% positive predictive value and 98.7% negative predictive value for detection of recurrence on the surgical scar. MRM detected 13 lesions remote from the scar. The overall sensitivity, specificity, positive predictive value and negative predictive value of MRM for detection of breast malignancy were 93.8%, 90%, 62.5% and 98.8%, respectively.

CONCLUSION

MRM is a sensitive method to differentiate recurrence from post-treatment changes at the prior lumpectomy site after conservative surgery and radiation therapy. The high negative predictive value of this technique can avoid unnecessary biopsies or surgical treatments.

Breast carcinomas with strong high-signal intensity on T2-weighted MR images: Pathological characteristics and differential diagnosis

PURPOSE

To investigate the histopathological characteristics of breast carcinomas with strong high-signal intensity (SHi) on T2-weighted (T2W) MR images (T2-SHi), and discuss the differential diagnosis between T2-SHi breast carcinomas and T2-SHi fibroadenomas.

MATERIALS AND METHODS

Thirty of 480 breast carcinomas examined by MRI were defined as tumors with T2-SHi (defined as homogeneous higher signal intensity (SI) compared to surrounding normal breast tissue on fat-suppressed T2W imaging (T2WI). They included eight mucinous and 22 nonmucinous carcinomas. The histopathological characteristics of T2-SHi breast carcinomas, their signal-to-noise ratios (SNRs) on T2WI, contrast-enhancement patterns, and morphology were compared with those of 22 non-T2-SHi breast carcinomas and 19 T2-SHi fibroadenomas.

RESULTS

In nonmucinous carcinomas T2-SHi was attributable to a mixture of background matrix, a higher proportion of cells than stroma, abundant cytoplasm, edematous stroma, and hemorrhage. The significantly high SNR (mean = 75) and enhancing internal septations seen in mucinous carcinomas, and the washout phenomenon, irregular border, absence of internal septation, and rim enhancement seen in nonmucinous carcinomas provide useful information for differentiating these tumors from T2-SHi fibroadenomas.

CONCLUSION

A mixture of several histopathological characteristics was associated with T2-SHi breast carcinomas. The combined information from T2WI and contrast-enhanced (CE) imaging may help distinguish T2-SHi breast carcinomas from T2-SHi fibroadenomas.

Patterns of enhancement on breast MR images: interpretation and imaging pitfalls

The role of dynamic contrast material-enhanced magnetic resonance (MR) imaging of the breast as an adjunct to the conventional techniques of mammography and ultrasonography has been established in numerous research studies. MR imaging improves the detection and characterization of primary and recurrent breast cancers and allows evaluation of the response to therapy. The breast imaging lexicon published by the American College of Radiology allows a standardized and consistent description of the morphologic and kinetic characteristics of breast lesions; however, there are many challenges in the interpretation of breast enhancement patterns and kinetics, and many imaging and interpretation pitfalls must be considered. New breast MR imaging techniques that are based on the use of molecular markers of malignancy may help improve lesion characterization. The margin characteristics of a lesion and the intensity of its enhancement at MR imaging 2 minutes or less after contrast material injection are currently considered the most important features for breast lesion diagnosis.

MR imaging features of pure mucinous carcinoma of the breast

OBJECTIVE

To characterize MR imaging features of pure mucinous carcinoma of the breast.

MATERIALS AND METHODS

MR images obtained from 16 women (age range, 29-81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings.

RESULTS

Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass.

CONCLUSIONS

MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.

Positive and Negative Predictive Values of BI-RADS®-MRI Descriptors for Focal Breast Masses

PURPOSE

The purposes of this study were to evaluate the positive and negative predictive values of the BI-RADS-MR descriptors of focal masses and to develop an interpretation model based on the kinetic and morphologic parameters.

METHODS

Retrospective review was performed of 171 consecutive focal breast masses. MR imaging was performed on a 1.5T system using the volumetric interpolated breath-hold examination sequence (mean partition thickness, 1.2 mm; time of acquisition, 35 s). Kinetic enhancement patterns were assessed by visually comparing signal intensity on the dynamic images acquired at 60 s and 4 min (washout, plateau, and persistent).

RESULTS

There were 126 malignant and 45 benign lesions. The most frequent morphological finding among the malignant lesions was heterogeneous internal enhancement in the delayed phase (96%; P<0.001); the most frequent finding in benign lesions was smooth margin or smooth shape/margin (80 to 82%; P<0.001). The features with the highest positive predictive value for carcinoma were spiculated margin (100%), delayed central enhancement (100%), delayed enhancing internal septations (97%), and irregular shape (97%). The characteristics with the highest diagnostic accuracy for malignancy were spiculated margin (100%) and heterogeneous enhancement following washout in the smooth shape/margin group (100%). The sensitivity, specificity, and positive and negative predictive values of an interpretation model based on a combination of the morphologic characteristics and kinetic information were 99%, 89%, 96%, and 98%, respectively.

CONCLUSION

A combination of morphologic criteria, particularly lesion shape/margin and internal heterogeneity, and kinetic information is useful for differentiating benign and malignant lesions.