Beyond BI-RADS: Nonmass Abnormalities on Breast Ultrasound

Abnormalities on breast ultrasound (US) images which do not meet the criteria for masses are referred to as nonmass lesions. These features and outcomes have been investigated in several studies conducted by Asian researchers. However, the term "nonmass" is not included in the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS) 5th edition for US. According to the Japan Association of Breast and Thyroid Sonology guidelines, breast lesions are divided into mass and nonmass. US findings of nonmass abnormalities are classified into five subtypes: abnormalities of the ducts, hypoechoic areas in the mammary glands, architectural distortion, multiple small cysts, and echogenic foci without a hypoechoic area. These findings can be benign or malignant; however, focal or segmental distributions and presence of calcifications suggest malignancy. Intraductal, invasive ductal, and lobular carcinomas can present as nonmass abnormalities. For the nonmass concept to be included in the next BI-RADS and be widely accepted in clinical practice, standardized terminologies, an interpretation algorithm, and outcome-based evidence are required for both screening and diagnostic US.

Nonmass Lesions on Breast US: An International Perspective on Clinical Use and Outcomes

Nonmass lesions (NMLs) on breast US are defined as discrete areas of altered echotexture compared to surrounding breast tissue and lack the 3-dimensionality of a mass. They are not a component of American College of Radiology BI-RADS, but they are a finding type included in the Japan Association of Breast and Thyroid Sonology lexicon. Use of the NML finding is routine in many Asian practices, including the Samsung Medical Center and Seoul National University Hospital, and their features and outcomes have been investigated in multiple studies. Nonmass lesions are most often observed when US is used to evaluate mammographic asymmetries, suspicious calcifications, and nonmass enhancement on MRI and contrast-enhanced mammography. Nonmass lesions can be described by their echogenicity, distribution, presence or absence of associated calcifications, abnormal duct changes, architectural distortion, posterior shadowing, small cysts, and hypervascularity. Malignant lesions, especially ductal carcinoma in situ, can manifest as NMLs on US. There is considerable overlap between the US features of benign and malignant NMLs, and they also must be distinguished from normal variants. The literature indicates that NMLs with linear or segmental distribution, associated calcifications, abnormal duct changes, posterior shadowing, and hypervascularity are suggestive of malignancy, whereas NMLs with only interspersed small cysts are usually benign fibrocystic changes. In this article, we introduce the concepts of NMLs, illustrate US features suggestive of benign and malignant etiologies, and discuss our institutional approach for evaluating NMLs and an algorithm that we use to guide interpretation in clinical practice.

Bright Is Not Always Better: A Pictorial Review of Hyperechoic Malignant Breast Masses

Hyperechogenic breast lesions are a relatively rare finding at breast ultrasonography and are traditionally thought to be benign. However, hyperechogenicity on the ultrasound alone does not provide enough evidence to rule out malignancy completely. We herein reported a short series of nine cases of echogenic malignant breast lesions, which include invasive ductal carcinoma, ductal carcinoma in situ, invasive lobular carcinoma, angiosarcoma, lymphoma, and metastasis to the breast. Echogenic breast lesions should be carefully evaluated and properly categorized based on any other suspicious sonographic characteristics and must be correlated with mammographic findings and clinical history to lower the threshold for biopsy and avoid delay in diagnosis. Hyperechogenicity should not be considered as a characteristically benign feature and should not supersede the less specifically benign features of the same lesion on the other examination.

Transversal Perspectives of Integrative Oncology Care in Gastric and Lobular Breast Cancer

The occurrence of gastric cancer has been associated with an increased risk of lobular breast tumors in a subset of patients harboring selected germline mutations. Among all, the germline alteration of the gene coding for E-Cadherin (CDH1) was associated with an increased risk of gastric cancer diffuse-histotype and lobular breast cancer. However, the risk assessment of breast neoplasms and the role of multiple prophylactic procedures in these patients has never been systematically addressed. In addition, the performance of the common screening procedures for lobular breast cancer like mammography is suboptimal. Therefore, recalling the need for a better articulation of the patient-centered strategies of surveillance for individuals with germline CDH1 and other similar alterations, to offer comprehensive approaches for prevention, early diagnosis, and treatment. Accordingly, this chapter aims to discuss the value and the role of integrated oncological care in the era of oncology sub-specializations. Additionally, it sheds light on how the harmonization across the health providers can enhance patient care in this setting.

Axillary Nodal Metastases in Invasive Lobular Carcinoma Versus Invasive Ductal Carcinoma: Comparison of Node Detection and Morphology by Ultrasound

Background: Invasive lobular carcinoma is more subtle on imaging compared with invasive ductal carcinoma; nodal metastases may also differ on imaging between these. Objective: To determine whether invasive lobular carcinoma and invasive ductal carcinoma differ in the detection rate by ultrasound (US) of metastatic axillary nodes and in metastatic nodes' US characteristics. Methods: This retrospective study included 695 women (median age 53 years) with breast cancer in a total of 723 breasts (76 lobular, 586 ductal, 61 mixed), with biopsy-proven axillary nodal metastases and who underwent pretreatment US. A single breast radiologist reviewed US images in patients with suspicious nodes on US and classified node number, size, and morphology. Morphologic assessment used a previously described classification based on the relationship between node cortex and hilum. Nodal findings were compared between lobular and ductal carcinoma. A second radiologist independently classified node morphology in 241 cancers to assess interreader agreement. Results: A total of 99 metastatic axillary nodes (15 lobular, 66 ductal, 18 mixed) were not visualized on US and were diagnosed by surgical biopsy. The remaining 624 metastatic nodes (61 lobular, 520 ductal, 43 mixed) were visualized on US and diagnosed by US-guided FNA. Thus, US detected the metastatic nodes in 80.3% for lobular carcinoma versus 88.7% for ductal carcinoma (p=.04). Among metastatic nodes detected by US, retrospective review identified ≥3 abnormal nodes in 50.8% of lobular carcinoma versus 69.2% of ductal carcinoma (p=.003); node size was ≤2.0 cm in 65.6% for lobular carcinoma versus 47.3% for ductal carcinoma (p=.03); morphology was type III/IV (diffuse cortical thickening without hilar mass effect) rather than type V/VI (marked cortical thickening with hilar mass effect) in 68.9% for lobular carcinoma versus 28.8% for ductal carcinoma (p<.001). Interreader agreement assessment for morphology exhibited kappa coefficient of 0.63 (95% CI, 0.54-0.73). Conclusion: US detects a lower percentage of nodal metastases in lobular than ductal carcinoma. Nodal metastases in lobular carcinoma more commonly show diffuse cortical thickening and with less hilar mass effect. Clinical Impact: A lower threshold may be warranted to recommend biopsy of suspicious axillary nodes detected on US in patients with lobular carcinoma.

Hyperechoic Lesions on Breast Ultrasound: All Things Bright and Beautiful?

Ultrasound (US) lexicon of the Breast Imaging Reporting and Data System (BI-RADS) defines an echogenic breast mass as a lesion that is hyperechoic in comparison with subcutaneous adipose tissue. However, at sonography, only 0.6 to 5.6% of breast masses are echogenic and the majority of these lesions are benign. approximately, 0.5% of malignant breast lesions appear hyperechoic. The various benign pathologic entities that appear echogenic on US are lipoma, hematoma, seroma, fat necrosis, abscess, pseudoangiomatous stromal hyperplasia, galactocele, etc. The malignant diagnoses that may present as hyperechoic lesions on breast US are invasive ductal carcinoma, invasive lobular carcinoma, metastasis, lymphoma, and angiosarcoma. Echogenic breast masses need to be correlated with mammographic findings and clinical history. Lesions with worrisome features such as a spiculated margin, interval enlargement, interval vascularity, or association with suspicious microcalcifications on mammography require biopsy. In this article, we would like to present a pictorial review of patients who presented to our department with echogenic breast masses and were subsequently found to have various malignant as well as benign etiologies on histopathology.

Added Value of Quantitative Ultrasound and Machine Learning in BI-RADS 4-5 Assessment of Solid Breast Lesions

The purpose of this study was to evaluate various combinations of 13 features based on shear wave elasticity (SWE), statistical and spectral backscatter properties of tissues, along with the Breast Imaging Reporting and Data System (BI-RADS), for classification of solid breast lesions at ultrasonography by means of random forests. One hundred and three women with 103 suspicious solid breast lesions (BI-RADS categories 4-5) were enrolled. Before biopsy, additional SWE images and a cine sequence of ultrasound images were obtained. The contours of lesions were delineated, and parametric maps of the homodyned-K distribution were computed on three regions: intra-tumoral, supra-tumoral and infra-tumoral zones. Maximum elasticity and total attenuation coefficient were also extracted. Random forests yielded receiver operating characteristic (ROC) curves for various combinations of features. Adding BI-RADS category improved the classification performance of other features. The best result was an area under the ROC curve of 0.97, with 75.9% specificity at 98% sensitivity.

Hyperechoic malignancies of the breast: Underlying pathologic features correlating with this unusual appearance on ultrasound

Hyperechogenicity in the breast on ultrasound (US) is usually regarded as a benign feature with only rare hyperechoic malignancies reported to date. In this study, we evaluated the pathologic findings on core needle biopsy of hyperechoic lesions and investigated the histologic features in malignancies that give rise to an echogenic pattern. A total of 163 core needle biopsies (CNB) were performed for "hyperechoic" or "echogenic" lesions between 1/1/05 and 7/31/17. Lesions were classified based on the proportion of hyperechoic areas identified. We found that all lesions with a homogenous hyperechoic pattern (>90% hyperechoic) were benign (n = 17), regardless of the type of margins. Malignancies were found in 21% (7/34, six invasive carcinomas and one lymphoma) of heterogenous lesions with ≥50% hyperechoic areas (all with noncircumscribed margins) and in 31% of lesions with <50% hyperechoic areas (19/61, 14 invasive carcinomas, two lymphomas, and three metastases), including five with circumscribed margins (one invasive carcinoma, one lymphoma, and three metastases). Two major US patterns were identified in malignant lesions, those with a hypoechoic center and hyperechoic rim, corresponding to a central tumor area with dense stroma and tumor cells infiltrating adipose tissue at the periphery ("rim pattern"), and a second "dispersed pattern" with hyperechoic areas distributed throughout the lesion. Hyperechoic malignancies were found to be comprised of a complex intermixture of elements of differing echogenicity including tumor cells, adipose tissue, and fluid (in tubules, stromal clefts, or blood vessels). Our findings support the importance of radiologists specifying the echogenic pattern of hyperechoic lesions, as heterogenous lesions are associated with a higher risk of malignancy and pathologists should be alert to the associated pathologic findings.

Hereditary lobular breast cancer with an emphasis on E-cadherin genetic defect

Recent studies have reported germline CDH1 mutations in cases of lobular breast cancer (LBC) not associated with the classical hereditary diffuse gastric cancer syndrome. A multidisciplinary workgroup discussed genetic susceptibility, pathophysiology and clinical management of hereditary LBC (HLBC). The team has established the clinical criteria for CDH1 screening and results' interpretation, and created consensus guidelines regarding genetic counselling, breast surveillance and imaging techniques, clinicopathological findings, psychological and decisional support, as well as prophylactic surgery and plastic reconstruction. Based on a review of current evidence for the identification of HLBC cases/families, CDH1 genetic testing is recommended in patients fulfilling the following criteria: (A) bilateral LBC with or without family history of LBC, with age at onset <50 years, and (B) unilateral LBC with family history of LBC, with age at onset <45 years. In CDH1 asymptomatic mutant carriers, breast surveillance with clinical examination, yearly mammography, contrast-enhanced breast MRI and breast ultrasonography (US) with 6-month interval between the US and the MRI should be implemented as a first approach. In selected cases with personal history, family history of LBC and CDH1 mutations, prophylactic mastectomy could be discussed with an integrative group of clinical experts. Psychodecisional support also plays a pivotal role in the management of individuals with or without CDH1 germline alterations. Ultimately, the definition of a specific protocol for CDH1 genetic screening and ongoing coordinated management of patients with HLBC is crucial for the effective surveillance and early detection of LBC.

Imaging features and conspicuity of invasive lobular carcinomas on digital breast tomosynthesis

OBJECTIVE

To review the imaging features of invasive lobular carcinoma (ILC) seen on digital breast tomosynthesis (DBT) in comparison with invasive ductal carcinoma (IDC), and to evaluate whether DBT could improve conspicuity and tumour size assessment of ILC in comparison with digital mammography (DM).

METHODS

Institutional review board with waiver of informed consent was obtained for this retrospective study. Patients with ILC or IDC who underwent DBT and DM at the time of diagnosis were included. DM and DBT images were reviewed in consensus by two breast radiologists in order to assess imaging features, conspicuity and maximum tumour diameter of ILC and IDC. Pathology on the surgical specimen was considered the standard of reference for assessment of tumour size.

RESULTS

43 patients (20 patients with ILC and 23 patients with IDC) were included. On DBT, compared with IDC, ILC presented less frequently as masses (40% vs 78%) (p = 0.01) and more frequently as isolated distortion (20% vs 0%) (p = 0.03). ILC presented more often as asymmetries (60%) than masses (20%) on DM (p = 0.02) but not on DBT (35% vs 40%; p = 1.00). Conspicuity of ILC was significantly higher on DBT than on DM (p = 0.002), while the difference between the two techniques was not significant for IDC (p = 0.2). Regarding ILC, concordance in tumour size measurement between DBT and pathology was fair (intraclass correlation coefficient = 0.24).

CONCLUSION

ILC rarely presented as dense masses but frequently demonstrated architectural distortion on DBT. DBT increased lesion conspicuity but failed to accurately assess tumour size of ILC. Advances in knowledge: (1) This study describes specific features of ILC on DBT. (2) It shows that DBT can improve conspicuity of ILC.

Malignant hyperechoic breast lesions at ultrasound: A pictorial essay

Malignant breast lesions are typically hypoechoic at sonography. However, a small subgroup of hyperechoic malignant breast lesions is encountered in clinical practice. We present a pictorial essay of a number of different hyperechoic breast malignancies with mammographic, sonographic and histopathologic correlation. Suspicious sonographic features in a hyperechoic lesion include inhomogeneity in echogenic pattern, an irregular margin, posterior acoustic shadowing and internal vascularity. A hyperechoic lesion at ultrasound does not discount the need to undertake histological assessment of a mammographically suspicious lesion.

E-cadherin germline mutation carriers: clinical management and genetic implications

Hereditary diffuse gastric cancer is an autosomic dominant syndrome associated with E-cadherin protein (CDH1) gene germline mutations. Clinical criteria for genetic screening were revised in 2010 by the International Gastric Cancer Linkage Consortium at the Cambridge meeting. About 40 % of families fulfilling clinical criteria for this inherited disease present deleterious CDH1 germline mutations. Lobular breast cancer is a neoplastic condition associated with hereditary diffuse gastric cancer syndrome. E-cadherin constitutional mutations have been described in both settings, in gastric and breast cancers. The management of CDH1 asymptomatic mutation carriers requires a multidisciplinary approach; the only life-saving procedure is the prophylactic total gastrectomy after thorough genetic counselling. Several prophylactic gastrectomies have been performed to date; conversely, no prophylactic mastectomies have been described in CDH1 mutant carriers. However, the recent discovery of novel germline alterations in pedigree clustering only for lobular breast cancer opens up a new debate in the management of these individuals. In this critical review, we describe the clinical management of CDH1 germline mutant carriers providing specific recommendations for genetic counselling, clinical criteria, surveillance and/ or prophylactic surgery.