Is there any added value to substitute the 2D digital MLO projection for a MLO tomosynthesis projection and its synthetic view when a 2D standard digital mammography is used in a one-stop-shop immediate reading mammography screening?

OBJECTIVES: Breast cancer screening consists of batch interpretation of two-view (cranio-caudal CC- and medio-lateral oblique MLO) digital mammography (DM) per breast. The DM-MLO view was substituted by an MLO-digital breast tomosynthesis (DBT) and its synthetic (2D-synthetic mammography (SM)-MLO) view. The performance of this hybrid protocol was evaluated in a one-stop-shop screening visit, providing immediate reading and additional work up. METHODS: Retrospective, observational review, comparing the cancer detection rate (CDR), breast US rates, and biopsy rates in 13,048 women screened with DM from June 2015 to November 2016 and 8639 women screened with SM-DBT/DM from January 2017 to July 2018. Chi-square tests or Fisher's exact tests were used to compare proportions between the two screening imaging methods. RESULTS: SM + DBT/DM significantly increased the overall CDR (10.8‰) versus DM (7.5‰) (p = 0.0120) with more invasive lobular carcinoma (14% versus 4%) (p = 0.0357) detected and overall more invasive cancers among women with breast density type B (p = 0.0411) and those aged between 60 and 70 (p = 0.0306). This was achieved at the expense of additional sonographic examinations performed (33.5% in DBT group versus 26.7% in DM group) (p < 0.0001), more BI-RADS category III assigned (1.8% in SM-DBT/DM group versus 1.5% in DM group) (p = 0.0443) and more biopsy rates (3.0 % in SM-DBT/DM group versus 1.7% in DM group) (p < 0.0001). CONCLUSIONS: Hybrid mammographic protocol replacing 2D-MLO by DBT-MLO and SM-MLO views in a one-stop-shop screening visit improved CDR, at the expense of more sonographic examinations, biopsies, and BI-RADS III lesions. Breast US alone detected 9.2% of all breast cancers in this cohort. KEY POINTS: • Hybrid protocol including MLO (DBT + SM) with 2D DM CC may improve CDR compared to standard 4 views 2D DM in a screening program providing immediate interpretation. • Adding screening breast US, when perceived necessary, in the same visit of a screening mammography, increases cancer detection rate of 9.2%. • Based on our results, hybrid protocol including DBT + SM in MLO plane and DM in CC plane could be safely implemented as a transition towards DBT and SM alone, without any compromise in the cancer detection ability. Our results may vary according to the properties of machines from different vendors.

Case 285: Primary Breast Lymphoma.

History A 25-year-old woman was referred to our breast clinic for assessment of a palpable mass in her left breast that developed quickly in 2 weeks. She denied any associated fever, chills, redness, or pain. She had no relevant medical or surgical history; no evidence of recent pregnancy, abortion, or breastfeeding; and no family history of breast cancer. Clinical examination enabled confirmation of a firm mass occupying the retroareolar region and the outer quadrant of the left breast with no skin retraction, edema, or erythema. There was no evidence of enlarged axillary lymph nodes. US of the left breast, bilateral breast MRI, and fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT were performed.

Idiopathic gigantomastia in a patient on polypharmacy.

Gigantomastia is an uncommon benign condition characterized by massive breast enlargement. It is most often due to hormonal imbalance secondary to puberty or pregnancy, or induced by a pharmacological agent but can also be idiopathic. Herein, we report a rare case of idiopathic gigantomastia in a 46-year-old female on antiepileptic multiple-drug therapy who underwent total bilateral mastectomy to relieve associated pain.

Case 285.

History A 25-year-old woman was referred to our breast clinic for assessment of a palpable mass in her left breast that developed quickly in 2 weeks. She denied any associated fever, chills, redness, or pain. She had no relevant medical or surgical history; no evidence of recent pregnancy, abortion, or breastfeeding; and no family history of breast cancer. Clinical examination enabled confirmation of a firm mass occupying the retroareolar region and the outer quadrant of the left breast with no skin retraction, edema, or erythema. There was no evidence of enlarged axillary lymph nodes. US of the left breast (Fig 1), bilateral breast MRI (Fig 2), and fluorine 18 fluorodeoxyglucose PET/CT (Fig 3) were performed.

Use of Intraoperative Radioguidance in Recurrent Merkel Carcinoma.

Merkel cell carcinoma is a rapidly progressive nonmelanoma skin cancer with a high risk of recurrence. When recurrence occurs, it is associated with poor prognosis and there is a lack of guidelines for the management of such cases. This article describes a challenging case in which the innovative use of iodine-125 radioactive seeds permitted us to precisely identify and resect two nonpalpable recurrent nodules. The safety and accuracy of the surgical procedure were compromised by the presence of scar tissue following two past resections and two courses of radiotherapy. Radioactive seed localization is a well-known procedure in breast cancer, demonstrating potential for an extended application in other cancer types and in complex clinical situations.

Venous malformation of the pectoral muscle depicted on mammogram.

Venous malformation of the pectoral muscle diagnosed on a mammogram of a 41-year-old patient presenting with clinical suspicion of a gynecomastia.

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.

Imaging features of pure and mixed forms of mucinous breast carcinoma with histopathological correlation.

METHODS:: A cross-sectional study identified cases of mucinous breast carcinoma from pathology records (2004-2012). Two radiologists classified imaging features by consensus and two pathologists classified cases into pure or mixed subtypes. Bi-variable analyses were performed using relevant statistical tests. RESULTS:: We identified 80 lesions in 77 female patients (median age 65 years, range 29-88): 58 lesions on mammograhy, 72 on ultrasound, and 25 on MRI. Statistically significant findings (p < 0.05) are as follows. On mammography, tumour margins tended to be indistinct (12, 48%) and spiculated (11, 44%) for pure and mixed lesions, respectively. Pure mucinous masses were less microcalcified (23, 77%) and mixed masses equally so. On ultrasound, pure tumours tended towards an irregular or oval shape (44, 42%) with mixed tumours having an irregular shape (78%). More pure tumours (53%) had posterior acoustic enhancement than mixed lesions (33%), and all pure tumours lacked posterior acoustic shadowing. Pure lesions had a heterogeneous echo pattern more than mixed tumours (78% vs 39%). On MRI, pure tumours tended towards a persistent kinetic curve (42%) whereas mixed tumours predominantly had a washout pattern (75%). Most pure tumours were T2 hyperintense (83%) whereas mixed lesions were T2 isointense or hyperintense (61%, 23%), respectively. CONCLUSION:: An analysis of imaging features can help to infer underlying histology of pure and mixed forms of mucinous breast carcinoma. ADVANCES IN KNOWLEDGE:: Pure mucinous carcinomas present less suspicious imaging features than mixed mucinous carcinomas and could be mistaken for non malignant lesions. An imaging analysis of mucinous breast carcinoma can help infer their underlying histology.

Comparative Evaluation of Iodine-125 Radioactive Seed Localization and Wire Localization for Resection of Breast Lesions.

PURPOSE: Radioactive seed localization (RSL) uses a titanium seed labeled with iodine-125 energy for surgery of nonpalpable breast lesions. RSL facilitates radiology-surgery scheduling and allows for improved oncoplasty compared with wire localization (WL). The purpose of this work was to compare the 2 techniques. METHODS: We performed a retrospective study of all breast lesions operated with RSL between February 2013 and March 2015 at our university institution, and compared with an equivalent number of surgeries performed with a single WL. Imaging and pathology reports were reviewed for information on guidance mode, accuracy of targeting, nature of excised lesion, size and volume of surgical specimen, status of margins, and reinterventions. RESULTS: A total of 254 lesions (247 women) were excised with RSL and compared with 257 lesions (244 women) whose surgery was guided by WL. Both groups were comparable in lesion pathology, guidance mode for RSL or WL positioning, and accuracy of targeting (98% correct). Mean delay between biopsy and surgery was 84 days for RSL versus 103 after WL (P = .04). No differences were noted after RSL or WL for surgical specimen mean weight, largest diameter, and volume excised. For malignancies, the rate of positive margins was comparable (2.8%-3%), with 5 of 10 women in the RSL group who underwent a second surgery displaying residual malignancy compared with 3 of 9 women in the WL group. CONCLUSIONS: RSL is safe and accurate, and has comparable surgical endpoints to WL. Because RSL offers flexible scheduling and facilitated oncoplasty, RSL may replace WL for resection of nonpalpable single breast lesions.

Lupus mastitis as a first manifestation of systemic disease: About two cases with a review of the literature.

Lupus mastitis is an uncommon manifestation of systemic lupus erythematosus (SLE) that affects the subcutaneous fat in the breast, much like lupus panniculitis, but additionally involves the mammary gland. We report on two women for whom lupus mastitis was the initial manifestation of SLE and provide a literature review of 34 additional cases reported in the Anglo-Saxon and French literature since 1971, making this the largest review to date. Lupus mastitis (LM) can manifest clinically as subcutaneous masses that may be painful, or may present cutaneous involvement such as thickening and discolouration. The radiologic manifestations of LM are broad and include calcifications, masses and asymmetries. Most often, excluding malignancy requires percutaneous biopsy, with histologic findings that are virtually pathognomonic for SLE. Thus, surgery is avoided and medical management can begin, antimalarial drugs and corticosteroids in most cases.

Is the outcome at surgery different when flat epithelial atypia and lobular neoplasia are found in association at biopsy?

OBJECTIVE: To assess the impact on the final outcome at surgery of flat epithelial atypia (FEA) when found concomitantly with lobular neoplasia (LN) in biopsy specimens compared with pure biopsy-proven FEA. METHODS: The approval from the institutional review board of the CHUM (Centre Hospitalier Universitaire de Montréal) was obtained. A retrospective review of our database between 2009 and 2013 identified 81 females (mean age 54 years, range 38-90 years) with 81 FEA biopsy-proven lesions. These were pure or associated with LN only in 59/81 (73%) and 22/81 (27%) cases, respectively. Overall, 57/81 (70%) patients underwent surgery and 24/81 (30%) patients underwent mammographic surveillance with a mean follow-up of 36 months. RESULTS: FEA presented more often as microcalcifications in 68/81 (84%) patients and were mostly amorphous in 49/68 (72%). After excluding radio pathologically discordant cases, pure FEA proved to be malignant at surgery in 1/41 (2%; 95% confidence interval 0.06-12.9). There was no statistically significant difference in the upgrade to malignancy whether FEA lesions were pure or associated to LN at biopsy (p = 0.4245); however, when paired in biopsy specimens, these lesions were more frequently associated with atypical ductal hyperplasia (ADH) at surgery than with pure FEA (p = 0.012). CONCLUSION: Our results show a 2% upgrade rate to malignancy of pure FEA lesions. When FEA is found in association with LN at biopsy, surgical excision yields more frequently ADH than pure FEA thus warranting close surveillance or even surgical excision. Advances in knowledge: The association of LN with FEA at biopsy was more frequently associated with ADH at surgery than with pure FEA. If a biopsy-proven FEA lesion is deemed concordant with the imaging finding, when paired with LN at biopsy, careful surveillance or even surgical excision is suggested.

Imaging Features Associated With Posttraumatic Breast Neuromas.

OBJECTIVE: The aim of this study is to review the clinical and imaging features of patients with a histopathologic diagnosis of posttraumatic breast neuromas. MATERIALS AND METHODS: We report eight biopsy-proven posttraumatic neuromas in six patients with a history of breast surgery. Mammographic, sonographic, and breast MRI examinations were reviewed according to the BI-RADS lexicon. In addition, the tail sign, a specific sign known to be associated with neuromas in other parts of the body, was assessed. RESULTS: Mammographic, MRI, and sonographic examinations were performed in three, four and all six patients, respectively. The neuromas were occult on the three mammograms performed but all of them were identified on ultrasound as hypoechoic masses with parallel orientation; seven of the eight neuromas (87.5%) had an oval shape with circumscribed margins. Strain elastography performed for two patients (three neuromas) showed benign features (benign elasticity scores and fat-to-lesion ratio). Half of the masses showed a tail sign (focal thickening of the nerve adjacent to posttraumatic neuroma, similar to the dural tail sign). Of five lesions investigated by MRI, two were occult on MRI. The remaining three were visible as isointense foci on T1-weighted images, with a benign type 1 enhancement curve. CONCLUSION: In patients who underwent breast surgery, a mass with benign features raises the possibility of a neuroma. Although the tail sign was present in half of the posttraumatic neuromas, imaging-guided biopsy remains the standard of care.

Breast imaging reporting and data system (BI-RADS) lexicon for breast MRI: interobserver variability in the description and assignment of BI-RADS category.

PURPOSE: To retrospectively evaluate interobserver variability between breast radiologists when describing abnormal enhancement on breast MR examinations and assigning a BI-RADS category using the Breast Imaging Reporting and Data System (BI-RADS) terminology. MATERIALS AND METHODS: Five breast radiologists blinded to patients' medical history and pathologic results retrospectively and independently reviewed 257 abnormal areas of enhancement on breast MRI performed in 173 women. Each radiologist described the focal enhancement using BI-RADS terminology and assigned a final BI-RADS category. Krippendorff's α coefficient of agreement was used to asses interobserver variability. RESULTS: All radiologists agreed on the morphology of enhancement in 183/257 (71%) lesions, yielding a substantial agreement (Krippendorff's α=0.71). Moderate agreement was obtained for mass descriptors - shape, margins and internal enhancement - (α=0.55, 0.51 and 0.45 respectively) and NME (non-mass enhancement) descriptors - distribution and internal enhancement - (α=0.54 and 0.43). Overall substantial agreement was obtained for BI-RADS category assignment (α=0.71). It was however only moderate (α=0.38) for NME compared to mass (α=0.80). CONCLUSION: Our study shows good agreement in describing mass and NME on a breast MR examination but a better agreement in predicting malignancy for mass than NME.

The Added Value of Statistical Modeling of Backscatter Properties in the Management of Breast Lesions at US.

PURPOSE: To develop a classification method based on the statistical backscatter properties of tissues that can be used as an ancillary tool to the usual Breast Imaging Reporting and Data System (BI-RADS) classification for solid breast lesions identified at ultrasonography (US). MATERIALS AND METHODS: This study received institutional review board approval, and all subjects provided informed consent. Eighty-nine women (mean age, 50 years; age range, 22-82 years) with 96 indeterminate solid breast lesions (BI-RADS category 4-5; mean size, 13.2 mm; range, 2.6-44.7 mm) were enrolled. Prior to biopsy, additional radiofrequency US images were obtained, and a 3-second cine sequence was used. The research data were analyzed at a later time and were not used to modify patient management decisions. The lesions were segmented manually, and parameters of the homodyned K distribution (α, k, and µn values) were extracted for three regions: the intratumoral zone, a 3-mm supratumoral zone, and a 5-mm infratumoral zone. The Mann-Whitney rank sum test was used to identify parameters with the best discriminating value, yielding intratumoral α, supratumoral k, and infratumoral µn values. RESULTS: The 96 lesions were classified as follows: 48 BI-RADS category 4A lesions, 16 BI-RADS category 4B lesions, seven BI-RADS category 4C lesions, and 25 BI-RADS category 5 lesions. There were 24 cancers (25%). The area under the receiver operating characteristic curve was 0.76 (95% confidence interval: 0.65, 0.86). Overall, 24% of biopsies (in 17 of 72 lesions) could have been spared. By limiting analysis to lesions with a lower likelihood of malignancy (BI-RADS category 4A-4B), this percentage increased to 26% (16 of 62 lesions). Among benign lesions, the model was used to correctly classify 10 of 38 fibroadenomas (26%) and three of seven stromal fibroses (43%). CONCLUSION: The statistical model performs well in the classification of solid breast lesions at US, with the potential of preventing one in four biopsies without missing any malignancy.

Molecular classification of infiltrating breast cancer: toward personalized therapy.

Breast cancer is a heterogeneous disease, which comprises several molecular and genetic subtypes, each with characteristic clinicobiologic behavior and imaging patterns. Traditional classification of breast cancer is based on the histopathologic features but offers limited prognostic value. Novel molecular characterization of breast cancer with cellular markers has allowed a new classification that offers prognostic value, with predictive categories of disease aggressiveness. These molecular signatures also open the door to personalized therapeutic options, with new receptor-targeted therapies. For example, invasive cancer subtypes such as the luminal A and B subtypes show better prognosis and response to hormone receptor-targeted therapies compared with the triple-negative subtypes; on the other hand, triple-negative tumors respond better than luminal tumors to chemotherapy. Tumors that display amplification of the oncogene ERBB2 (also known as the HER2/neu oncogene) respond to drugs directed against this oncogene, such as trastuzumab. The imaging aspects of tumors correlate with molecular subgroups, as well as other pathologic features such as nuclear grade. Smooth tumor margins at mammography may be suggestive of a triple-negative breast cancer, and a human epidermal growth factor receptor 2 (HER2)-positive tumor is characteristically a spiculated mass with calcifications. Low-grade ductal carcinoma in situ (DCIS) is better detected with mammography, although magnetic resonance (MR) imaging may allow better characterization of high-grade DCIS. MR imaging diffusion sequences show higher values for the apparent diffusion coefficient for triple-negative and HER2-positive subtypes, compared with luminal A and B tumors. MR imaging is also a useful tool in the prediction of tumor response after chemotherapy, especially for triple-negative and HER2-positive subtypes.