Breast Core Biopsy Research Articles

PO3 Borderline lesions diagnosed on breast core biopsy: Frequency of atypia and carcinoma on surgical excision – Local clinical experience

PO3 Borderline lesions diagnosed on breast core biopsy: Frequency of atypia and carcinoma on surgical excision – Local clinical experience

Upgrade rate of mucocoele-like lesion diagnosed on breast core biopsy for a local population

Upgrade rate of mucocoele-like lesion diagnosed on breast core biopsy for a local population

Isolated Atypical Lobular Hyperplasia Diagnosed on Breast Biopsy: Low Upgrade Rate on Subsequent Excision With Long-Term Follow-up.

- The upgrade rate to carcinoma on excision for atypical lobular hyperplasia diagnosed on breast biopsy is controversial. - To review cases with isolated atypical lobular hyperplasia on biopsy to establish the rate of upgrade on excision and correlate with long-term follow-up. - A database search was performed for 191 months to identify breast core biopsies with isolated atypical lobular hyperplasia. Cases with other atypical lesions in the biopsy or discordant radiologic-pathologic findings were excluded. Invasive carcinoma and ductal carcinoma in situ were considered upgraded pathology on excision. Patients without and with a history of, or concurrent diagnosis of, breast carcinoma were compared. - Eighty-seven cases of isolated atypical lobular hyperplasia on biopsy underwent subsequent excision, which resulted in 3 upgraded cases (3.4%). All 3 cases with immediate upgrades revealed ductal carcinoma in situ. Upgrade was higher in patients with a concurrent diagnosis of breast carcinoma (2 of 26 and 1 of 61; 7.7% versus 1.6%, respectively). Follow-up information was available for 63 patients (57.8 ± 43.9 months; range, 6-183 months). Overall, 13% of patients without a history of breast carcinoma had a future breast cancer event, with the majority (83%) presenting in the contralateral breast. - With careful radiologic-pathologic correlation, the upgrade rate for isolated atypical lobular hyperplasia on biopsy is low, and a more conservative approach may be appropriate.

Clinical breast concerns in low-risk pediatric patients: practice review with proposed recommendations.

Fibroadenoma is overwhelmingly the most common pediatric breast lesion. Breast malignancy is quite uncommon in children, most frequently metastatic or hematological malignancy. Core biopsy has largely replaced excision for diagnosis of breast masses in adults. The purpose of this study is two-fold: (1) compare utilization at our institution of interventional procedures vs. surgery for breast mass diagnosis in patients ≤18years and (2) propose guidelines for breast imaging and biopsy in this population. We extracted data for all patients ≤18 who, between 2004 and 2016, underwent either (a) imaging and/or intervention procedure, or (b) breast surgery, from the Radiology Information System and Pathology Data System, respectively. We recorded age, gender, imaging, procedure, lesion size and histopathology. We found 1,050 pediatric patients ≤18years who underwent diagnostic breast ultrasound between 2004 and 2016. Of these, 168 patients underwent 199 interventional procedures. One hundred thirty patients underwent 160 core biopsies of solid lesions. Core biopsy pathology diagnosed benign lesions in 99%, of which 84.3% were fibroadenomas (n=135). One malignancy was diagnosed, B cell lymphoma. Two hundred three patients underwent surgical excision for 266 discrete lesions, and 89% were fibroadenomas. Seven benign phyllodes tumors were surgically diagnosed. No malignancies were diagnosed. Core biopsy in patients 18years and younger is well-tolerated, has few risks, and is preferable to surgery in developing breasts, but the goal is to avoid any breast procedure whenever possible. We propose guidelines for pediatric breast imaging, follow-up, core biopsy and excisions.

Nonneoplastic Inflammatory Conditions of the Breast

Although rare, nonneoplastic inflammatory breast conditions are encountered in both community and academic settings. Imaging characteristics of these breast conditions can closely resemble breast carcinoma; and, therefore, core breast biopsy often is necessary to exclude malignancy. Knowledge of the radiologic and histopathologic features can help guide management and reassure clinicians and patients. Our aim in this article is to discuss specific imaging characteristics, management, and treatment options for nonneoplastic inflammatory conditions of the breast, which can be divided into immunologic, granulomatous, and infectious causes (Figure 1).

Mucocele-like lesions diagnosed on breast core biopsy: Low risk of upgrade and subsequent carcinoma.

Mucocele-like lesions of the breast diagnosed on core biopsy are usually excised to exclude the possibility of partial sampling of an invasive mucinous carcinoma. The goal of this study was to correlate the pathologic and radiologic features of mucocele-like lesions to determine if excision is mandatory. Over a 16 year period we identified 32 patients with mucocele-like lesions diagnosed on 27 (84%) stereotactic and 5 (16%) ultrasound-guided core biopsies. The indications for core biopsy were: calcifications in 24 (75%), a mass in 7 (22%), and a mass with calcifications in 1 (3%). There were 22 (69%) mucocele-like lesions without atypia and 10 (31%) with atypical ductal hyperplasia or detached groups of atypical cells. Of the 22 mucocele-like lesions without atypia, 19 (86%) were excised: 15/19 (79%) were benign, 3/19 (16%) had atypical ductal hyperplasia and 1/19 (5%) had ductal carcinoma in situ. None of the patients with mucocele-like lesions without atypia were upgraded to invasive carcinoma. The single patient who was upgraded to low-grade ductal carcinoma in situ had a history of ductal carcinoma in situ in the same breast. Of the 10 patients with mucocele-like lesions with atypia, 9 (90%) were excised: 5/9 (56%) were benign, 1/9 (11%) had atypical ductal hyperplasia and 3/9 (33%) had invasive carcinoma. Of the patients with mucocele-like lesions with atypia who were upgraded to invasive carcinoma, one had a BIRADS 5 mass and discordant pathology and one had a history of Hodgkin lymphoma and mantle radiation. There were 24 patients with mucocele-like lesions with or without atypia who were not upgraded on excision, and none developed breast cancer after a median of 51 months (range 7-192). These findings indicate that mucocele-like lesions without atypia are unlikely to be upgraded on excision and are associated with a low risk for the subsequent development of carcinoma.

Video-Based Teaching of Image-Guided Breast Interventions: Stereotactic Core Biopsy Using a Prone Table.

The introduction of new technologies and teaching strategies to educate the digital learner creates the potential for a better and more standardized training experience across programs. Thus, we sought to create an instructional video on stereotactic core breast biopsy that simulates best practices and could be readily accessed by training programs to improve and standardize resident education. At our institution, we use the video and questions as part of a flipped classroom educational activity. Residents are requested to complete the questions at home and watch the video. They then take the posttest questions during the lecture period, at which time the answers are reviewed and there is additional discussion of the procedure. The tests contain both video-related questions and control questions. After viewing the video, there was a 30% mean improvement in the video-related questions compared to a 0% improvement in the control set of questions. An instructional video on stereotactic core biopsy was created with associated assessment questions that can be used at any institution for the purposes of improving and standardizing training in breast imaging procedures. This resource can be especially useful for programs where trainees have limited procedure exposure.

Pleomorphic Lobular Carcinoma in Situ Diagnosed by Breast Core Biopsy: Clinicopathologic Features and Correlation With Subsequent Excision

IntroductionPleomorphic lobular carcinoma in situ (PLCIS) is a variant of LCIS with high-grade morphologic features. The number of case series studying PLCIS is limited, and clinical management of patients with PLCIS is controversial. We report a breast core biopsy (BCBx) series of PLCIS. Materials and MethodsWe reviewed 37 cases of PLCIS with or without microinvasion diagnosed by BCBx. PLCIS was defined as dyscohesive cells showing acinar expansion and loss of immunohistochemical membranous expression of e-cadherin or beta-catenin with nuclear pleomorphism with at least 2- to 3-fold variation in nuclear size, membrane irregularities, and variably prominent nucleoli. Clinical information and findings on excision were evaluated. ResultsThirty-one (84%) patients presented with mammographic calcifications, 4 (11%) presented with ultrasound findings, 1 (3%) presented with magnetic resonance imaging enhancement, and 1 (3%) with combined imaging abnormality. The mean patient age was 62.3 years. Nineteen patients (51%) had a family history of breast cancer. Microinvasion was present on BCBx in 9 (24%) of the 37 patients. Excision, available in 34 patients, demonstrated invasive carcinoma in 24 (65%), which was multifocal in 11 (46%). Twenty-three patients with PLCIS without microinvasion on BCBx, and without known history of ipsilateral invasive cancer, underwent excision; 14 of these patients demonstrated invasive carcinoma, representing an upgrade to invasive carcinoma of 60%. ConclusionWe report the largest BCBx series of PLCIS and confirm its aggressive biology and frequent association with multifocal invasive lobular carcinoma, as well as frequent presentation in patients with a family history of breast cancer. Our results support excision to negative margins.

Concordance of DNA methylation profiles between breast core biopsy and surgical excision specimens containing ductal carcinoma in situ (DCIS)

The utility and reliability of assessing molecular biomarkers for translational applications on pre-operative core biopsy specimens assume consistency of molecular profiles with larger surgical specimens. Whether DNA methylation in ductal carcinoma in situ (DCIS), measured in core biopsy and surgical specimens are similar, remains unclear. Here, we compared genome-scale DNA methylation measured in matched core biopsy and surgical specimens from DCIS, including specific DNA methylation biomarkers of subsequent invasive cancer. DNA was extracted from guided 2mm cores of formalin fixed paraffin embedded (FFPE) specimens, bisulfite-modified, and measured on the Illumina HumanMethylation450 BeadChip. DNA methylation profiles of core biopsies exhibited high concordance with matched surgical specimens. Within-subject variability in DNA methylation was significantly lower than between-subject variability (all P<2.20E−16). In 641 CpGs whose methylation was related with increased hazard of invasive breast cancer, lower within-subject than between-subject variability was observed in 92.3% of the study participants (P<0.05). Between patient-matched core biopsy and surgical specimens, <0.6% of CpGs measured had changes in median DNA methylation >15%, and a pathway analysis of these CpGs indicated enrichment for genes related with wound healing. Our results indicate that DNA methylation measured in core biopsies are representative of the matched surgical specimens and suggest that DCIS biomarkers measured in core biopsies can inform clinical decision-making.

Ultrasound-guided Breast Biopsy in the Resource-limited Setting: An Initial Experience in Rural Uganda

<strong>Purpose:</strong> To describe the methodology and initial experience behind creation of an ultrasoundguided percutaneous breast core biopsy program in rural Uganda. <strong>Methods and Materials:</strong> Imaging the World Africa (ITWA) is the registered non-governmental organization division of Imaging the World (ITW), a not-for-profit organization whose primary aim is the integration of affordable high-quality ultrasound into rural health centers. In 2013, ITWA began the pilot phase of an IRB-approved breast care protocol at a rural health center in Uganda. As part of the protocol’s diagnostic arm, an ultrasound-guided percutaneous breast core biopsy training curriculum was implemented in tandem with creation of regionally supplied biopsy kits. <strong>Results</strong>: A surgeon at a rural regional referral hospital was successfully trained and certified to perform ultrasound-guided percutaneous breast core biopsies. Affordable and safe biopsy kits were created using locally available medical supplies with the cost of each kit totaling $10.62 USD. <strong>Conclusion:</strong> Successful implementation of an ultrasound-guided percutaneous breast core biopsy program in the resource-limited setting is possible and can be made sustainable through incorporation of local health care personnel and regionally supplied biopsy materials. Our hope is that ITWA’s initial experience in rural Uganda can serve as a model for similar programs in the future.

Upgrade Rate and Imaging Features of Atypical Apocrine Lesions.

The purpose of our work was to identify imaging features of atypical apocrine lesions and determine the rate of upgrade to ductal carcinoma insitu (DCIS) or invasive carcinoma at excision after such a diagnosis on percutaneous breast biopsy. From January 1, 2006, through October 8, 2013, a total of 33,157 breast core biopsies were performed at University of Pittsburgh Medical Center. Of those, 58 (0.2%) showed atypical apocrine lesions. For 24, atypical apocrine adenosis (AAA) or atypical apocrine metaplasia (AAM) was the only risk lesion, with no known ipsilateral malignancy, and the results of excision were available. The median patient age was 58years (range 43-88). Among 24 atypical apocrine lesions (20 AAA and 4 AAM), four (16.7%; 95% confidence interval: 4.7, 37.4) were upgraded at excision: one invasive ductal carcinoma (grade 2, 0.2cm, estrogen receptor positive, progesterone receptor positive, HER2/Neu negative) and three DCIS (two grade 3, one grade 2). All four upgraded lesions were AAA (20%; 4/20). Twelve AAA were seen as an irregular (n=9) or circumscribed (n=3) mass on ultrasound; three masses had calcifications. Six of 20 (30%) AAA were seen on biopsy of calcifications only and calcifications were within two AAA lesions at histopathology. One AAA (1/20, 5%) was asymmetry only, and one (1/20, 5%) a persistently enhancing MR focus. All four malignancies were masses on ultrasound (three irregular, one circumscribed), and three malignancies had calcifications (two coarse heterogeneous, one amorphous). While concordant with an irregular or circumscribed mass on imaging, with or without amorphous or coarse heterogeneous calcifications, AAA merits excision with a 20% upgrade rate to malignancy. Further study of AAM is warranted.

Accuracy of clinical and ultrasound examination of palpable breast lesions in a resource-poor society

Background: Palpable breast masses are common presentations in resource-poor societies. Clinical and ultrasonographic breast examinations are commonly available means of evaluation. Objective: The objective of this study was to compare the accuracy of clinical breast examination (CBE) and ultrasonography in the diagnosis of palpable breast masses. Methodology: Consenting females presenting with palpable breast masses at the general surgical outpatient clinic were assessed clinically by the most senior surgeon, ultrasonographically by two radiologists, and the diagnosis compared with histologic examination. Results: One hundred and thirteen patients were recruited during the study period from January 2013 to April 2014. Of these, 53 patients (46.9%) had breast core biopsy, while 60 (53.1%) had open surgical biopsy. Only 67 (59.3%) patients had their histological results available. The mean age was 41.58 years (range 16–78). CBE achieved a sensitivity of 82.1%, specificity 67.9%, positive predictive value (PPV) 78%, negative predictive value 73%, overall accuracy 76.1%, false positive rate 32.1%, and false negative rate 17.9%. Breast ultrasonography had a sensitivity of 86.8%, specificity 72.4%, PPV 80.5%, negative predictive value 80.8%, overall accuracy 80.6%, false positive rate 27.6%, and false negative rate 13.2%. Conclusion: This study revealed no statistical significant difference between the accuracy of CBE and breast ultrasonography. We recommend that both should be used in the evaluation of palpable breast masses.

Invasive Ductal Carcinoma Breast: How Neoadjuvant Chemotherapy Affects the Status of Estrogen Receptor, Progesterone Receptor and HER2/Neu-A Tertiary Care Centre Study.

Determination of Estrogen Receptor (ER), Progesterone Receptor (PR) and HER2/neu in primary Invasive Ductal Carcinoma (IDC) breast is the standard of care parameter for determining treatment options. Whether or not Neoadjuvant Chemotherapy (NAC) affects the receptor status is still an unanswered question. To compare immunohistochemical (IHC) profiles of ER, PR and HER2/neu in primary IDC breast before and after NAC to assess the subsequent effects on receptor status. Thirty two patients diagnosed with primary IDC breast who had a previous breast core biopsy with complete IHC profile followed by NAC and Modified Radical Mastectomy (MRM) were included. For each case demographic and histologic data was collected, including age, grade, amount of necrosis post NAC and IHC panel for ER, PR and HER2/neu in core biopsies. The same IHC panel was applied on Post NAC MRM specimen. Pre- and post NAC IHC expression was compared. Patients ranged from 30 years to 75 years in range. ER, PR and HER2/neu status of core biopsies and MRM specimen were compared and overall agreement was noted. Comparison for each receptor was done using McNemar's test and significance was calculated. There was no statistically significant difference in ER and Her2/neu expression between pre- and post-NAC specimens. However, a statistically significant loss of PR expression was noted between the two groups. Accurate determination of ER, PR and Her2/neu status in primary IDC breast is important to guide further treatment. Change in receptor status post NAC may warrant corresponding change in hormonal therapy.

Simultaneous automatic scoring and co-registration of hormone receptors in tumor areas in whole slide images of breast cancer tissue slides.

Automation of downstream analysis may offer many potential benefits to routine histopathology. One area of interest for automation is in the scoring of multiple immunohistochemical markers to predict the patient's response to targeted therapies. Automated serial slide analysis of this kind requires robust registration to identify common tissue regions across sections. We present an automated method for co-localized scoring of Estrogen Receptor and Progesterone Receptor (ER/PR) in breast cancer core biopsies using whole slide images. Regions of tumor in a series of fifty consecutive breast core biopsies were identified by annotation on H&E whole slide images. Sequentially cut immunohistochemical stained sections were scored manually, before being digitally scanned and then exported into JPEG 2000 format. A two-stage registration process was performed to identify the annotated regions of interest in the immunohistochemistry sections, which were then scored using the Allred system. Overall correlation between manual and automated scoring for ER and PR was 0.944 and 0.883, respectively, with 90% of ER and 80% of PR scores within in one point or less of agreement. This proof of principle study indicates slide registration can be used as a basis for automation of the downstream analysis for clinically relevant biomarkers in the majority of cases. The approach is likely to be improved by implantation of safeguarding analysis steps post registration. © 2016 International Society for Advancement of Cytometry.

Novel biomarkers in primary breast core biopsies to predict poor response to neoadjuvant chemotherapy and appearance of metastases.

Drug resistance has been one of the major obstacles limiting the success of cancer chemotherapy. In two thirds of breast cancer patients, large (>1cm) residual tumors are present after neoadjuvant chemotherapy (NCT). The residual tumor and involved nodes have been indicators of relapse and survival very important in breast cancer. The goal of this preliminary study was to assess the predictive significance of a panel of molecular biomarkers, related with the response to treatment or drug resistance to NCT, as determined on the diagnostic tumor. The expression of 22 proteins was examined using immunohistochemistry in tissue microarrays (TMA) from 115 patients of stage II-III breast cancer, treated with NCT. Among studied proteins, there are some that are anti-apoptotic, pro-proliferative, cancer stem cell markers and the Vitamin D Receptor. Other proteins are involved in the identification of molecular subtype, cell cycle regulation or DNA repair. Next, a predictive signature of poor response was generated from independent markers of predictive value. Tumors that expressed four or five conditions (biomarkers of chemoresistance with a determinated cutoff) were associated with a 9-fold increase in the chances of these patients of having a poor response to NCT. Additionally, we also found a worse prognostic signature, generated from independent markers of prognostic value. Tumors which expressed two or three conditions of worst prognostic, were associated with a 6-fold reduction in Distant Disease Free Survival. In conclusion, finding biomarkers of chemoresitance (ypTNM II-III) and metastases can become a stepping stone for future studies that will need to be assessed in a bigger scale.

Intraobserver Agreement on Histopathologic Evaluations of Core Breast Biopsies.

The number of performed core biopsies of the breast as diagnostic workup is increasing in many European countries. We measured the intraobserver variability in pathological assessment of breast core biopsies. Furthermore, we studied potential modifiers of agreement between the assessments. Two hundred and fifty-six breast biopsies were evaluated twice in a blinded fashion by two pathologists. We calculated the observed and the chance-corrected (weighted) intraobserver agreement (kappa) using the B-categorization scheme (B1: normal or not interpretable, B2: benign, B3: benign but of uncertain biological potential, B4: suspicious of malignancy, B5: malignant). The observed agreement between the first and the second assessments were 0.80 (95% CI: 0.75-0.85) for pathologist 1 and 0.81 (95% CI: 0.76-0.86) for pathologist 2. The chance-corrected agreements were 0.85 (95% CI: 0.80-0.89) and 0.81 (95% CI: 0.76-0.87), respectively. The most frequent disagreement was between B1 and B2 for pathologist 1 (N = 34 out of 50 disagreements, 68%) and between B2 and B3 for pathologist 2 (N = 23 out of 48 disagreements, 48%). Our study shows that the chance-corrected agreement between the histopathological evaluations of breast biopsies based on the B-categorization scheme is almost perfect. The level of agreement is modified by biopsy technique and by the level of suspicion of the mammographic lesion.

Ductal carcinoma insitu: Is core needle biopsy ever enough?

This study investigates the rate of histological underestimation of invasive breast carcinoma following diagnosis of ductal carcinoma insitu (DCIS) on a radiologically guided core needle biopsy, and factors that may influence this upgrade rate. A retrospective review of the results of breast core biopsies performed between 1st January, 2005 and 2nd July, 2014 was conducted, and those with a diagnosis of DCIS were identified. Data including final excision pathology, lesion size, performing radiologist, core biopsy system and guidance method used were collected and included in the analysis. We report an overall upgrade rate to invasive cancer of 20.5% (95% CI=16.1-24.9%). No statistically significant relationship was identified between biopsy systems used or clinicians performing the biopsies and the rate of upgrade to invasive cancer. Initially a statistically significant relationship was demonstrated between upgrade rates and lesion size, DCIS grade, as well as guidance method. Subsequent multivariable analysis showed no statistically significant relationship between guidance method and upgrade rates but a trend towards statistical significance (P<0.1). Our recommendation is to inform women diagnosed with DCIS preoperatively in our programme, that there is a one in five chance the diagnosis will prove to be invasive cancer on definitive surgery. This is particularly important for women contemplating whether or not to undergo surgery for DCIS. Additionally, as the most significant predictor of upgrade rate demonstrated in this study is increasing lesion size, consideration should be given to increasing the number of core samples taken of larger lesions.

Lobular neoplasia diagnosed on breast Core biopsy: frequency of carcinoma on excision and implications for management.

The appropriate follow-up and treatment for patients with a core biopsy diagnosis of lobular neoplasia (atypical lobular hyperplasia or lobular carcinoma in situ) remains controversial. Several studies have attempted to address this issue, with recommendations ranging from close clinical follow-up or surveillance to mandatory surgical excision in all cases. We report the findings at our institution, where virtually every core needle biopsy diagnosis of lobular neoplasia results in follow-up excision. The goal of the study was to identify potential predictors of upgrade to a more significant lesion. We identified 76 patients over a 15-year period with a core biopsy diagnosis of pure lobular neoplasia and no other high-risk lesions. Subsequent surgical excision identified 10 cases (13%) that were upgraded to carcinoma. Upgrade diagnoses included invasive ductal carcinoma (n=1), invasive lobular carcinoma (n=4), ductal carcinoma in situ (n=3), and pleomorphic lobular carcinoma in situ (n=2). All 10 upgraded cases had imaging findings suspicious for malignancy including irregular masses, asymmetric densities, or pleomorphic calcifications. Of the 10 upgraded cases, 7 were diagnosed as lobular carcinoma in situ on core biopsy. The data support a role for radiologic-pathologic correlation in the evaluation of suspicious breast lesions and suggest that the extent of lobular neoplasia in core biopsy specimens may be an indicator of the likelihood of upgrade to carcinoma.

Core Breast Biopsies Showing Lobular Carcinoma In Situ Should Be Excised and Surveillance Is Reasonable for Atypical Lobular Hyperplasia.

The purpose of this article is to determine the upgrade rate to ductal carcinoma in situ (DCIS) or invasive carcinoma at excision at the same site after percutaneous breast biopsy findings of atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS) using current imaging and strict pathologic criteria. From January 2006 through September 2013, 32,960 breast core biopsies were performed; 1084 (3.3%) core biopsies found ALH or classic LCIS. For 447 lesions in 433 women, this was the only high-risk lesion at that site, with no ipsilateral malignancy, and results of excision were available. Among the 447 lesions, 22 (4.9%) were malignant at excision, including 10 invasive carcinomas (two grade 2 and eight grade 1; all node negative) and 12 DCIS. The upgrade rate of LCIS was 9.3% (10/108; 95% CI, 5.1-16.2%) and that of ALH was 3.5% (12/339; 95% CI, 2.0-6.1%; p = 0.02). After excluding five cases with radiologic-pathologic discordance and reclassifying one core from ALH to LCIS at review, the upgrade rate for LCIS remained higher (8.4%; 9/107; 95% CI, 4.5-15.2%) than that for ALH (2.4%; 8/335; 95% CI, 1.2-4.6%; p = 0.01). Excision is recommended for LCIS on core biopsy because of its 8.4-9.3% upgrade rate. Excluding discordant cases, patients with other high-risk lesions or concurrent malignancy, the risk of upgrade of ALH was 2.4%. Surveillance at 6, 12, and 24 months can be performed in lieu of excision because a short delay in diagnosis of the few malignancies is not expected to cause harm.

Core Biopsy of Vascular Neoplasms of the Breast: Pathologic Features, Imaging, and Clinical Findings.

Vascular lesions (VLs) of the breast present a diagnostic challenge on breast core biopsy (BCBx). We report on 27 VLs presenting on BCBx. The mean patient age was 60 years, and mean size was 7.5 mm (range, 1.6 to 16 mm). Presentation included palpable mass in 6 (22%), incidental in 6 (22%), and an imaging abnormality in 15 (56%) cases. Imaging impression included hematoma (24%), lymph node (10%), fat necrosis (10%), tortuous vessel (5%), and not provided in 52%. The lesions were classified on the basis of BCBx or BCBx and excision (available in 16 pts) as follows: 1 low-grade angiosarcoma, 8 angiolipomas, 6 capillary hemangiomas, 4 cavernous hemangiomas, 2 hemangiomas (not otherwise specified), 1 papillary endothelial hyperplasia, and 5 perilobular hemangiomas. The angiosarcoma was 9 mm, detected incidentally by magnetic resonance imaging, and showed dissection of stromal collagen, infiltration of glands, high cellularity, moderate cytologic atypia, scant mitotic activity, and Ki-67 reactivity of 10%. Among the 26 benign VLs, worrisome histologic features were noted in 14 on BCBx, including anastomosing vascular channels in 9, moderate cytologic atypia in 4, high cellularity in 2, Ki-67>10% in 2, mitotic activity in 1, and infiltration of glands in 1. Of the 12 VLs without worrisome features, the lesion extended to edge of core in 8, precluding complete evaluation. BCBx of VLs presents diagnostic challenges due to overlapping clinicopathologic and radiologic features with low-grade angiosarcoma. If completeness of removal is documented on BCBx, and cytoarchitectural changes are not worrisome, follow-up could be considered rather than excision. However, only 4 of these cases fulfilled those criteria.