Lobular neoplasia detected at MRI-guided biopsy: imaging findings and outcomes.

OBJECTIVE: To review MRI findings of pure lobular neoplasia (LN) on MRI guided biopsy, evaluate surgical and clinical outcomes, and assess imaging findings predictive of upgrade to malignancy. METHODS: HIPAA compliant, IRB-approved retrospective review of our MRI-guided breast biopsy database from October 2008-January 2015. Biopsies yielding atypical lobular hyperplasia or lobular carcinoma in situ were included in the analysis; all biopsy slides were reviewed by a dedicated breast pathologist. Imaging indications, MRI findings, and histopathology were reviewed. Statistical analysis was performed using the two-tailed Fisher exact-test and the t-test, and 95% CIs were determined. A p < 0.05 was considered statistically significant. RESULTS: Database search yielded 943 biopsies in 785 patients of which 65/943 (6.9%) reported LN as the highest risk pathologic lesion. Of 65 cases, 32 were found to have LN as the dominant finding on pathology and constituted the study population. All 32 findings were mammographically and sonographically occult. Three of 32 (9.3%) cases of lobular neoplasia were upgraded to malignancy, all LCIS (one pleomorphic and two classical). The most common MRI finding was focal, heterogenous non-mass enhancement with low T2 signal. No clinical features or imaging findings were predictive of upgrade to malignancy. CONCLUSION: Incidence of pure lobular neoplasia on MRI guided biopsy is low, with comparatively low incidence of upgrade to malignancy. No imaging or clinical features are predictive of upgrade on surgical excision, therefore, prudent radiologic-pathologic correlation is necessary.

Do benign-concordant breast MRI biopsy results require short interval follow-up imaging? Report of longitudinal study and review of the literature.

OBJECTIVE: The objectives of this study were to examine the frequency and outcomes of short interval imaging follow up of benign, concordant breast MRI biopsies and review the published literature on this topic. MATERIALS AND METHODS: This was an IRB-approved, HIPAA compliant retrospective review of women undergoing MRI-guided breast biopsies between October 1, 2008 and December 31, 2014. Patients with malignant or high risk lesions with recommendation for excision, discordant cases, and those undergoing breast conservation therapy in same quadrant, chemotherapy or mastectomy were excluded. At least 2 years imaging and/or clinical follow-up without development of cancer in the same quadrant as the biopsy was set as the benchmark to confirm benign etiology. A PubMed search of similar articles through 2018 was also performed for the literature review. RESULTS: 943 consecutive MRI-guided biopsies were performed in 785 women. Of these, 378/943 (40.1%) were benign and met inclusion criteria. Eleven cases were recommended for and underwent repeat MRI-guided biopsy or excision, 2 of which were malignant. The overall false negative rate for benign concordant MRI-guided biopsy was 2/378, 0.5% (95% CI 0.02 to 2.0%). Literature search demonstrated five articles with similar methodologies yielding 628 additional cases of benign concordant breast biopsies. Nine of these cases were eventually diagnosed as malignancy with a false negative rate of 1.4%. Combined with our data, the overall false negative rate is 1.1%. CONCLUSIONS: Short interval follow-up exams for benign concordant MRI-guided breast biopsies may not be necessary given the low malignancy rate.

A prospective comparative study to evaluate the displacement of four commercially available breast biopsy markers.

OBJECTIVE: Radiopaque markers are commonly deployed following breast biopsies to indicate the location of the targeted lesion. A frequently encountered complication is the displacement of these markers. This study compared the degree of displacement among four newer generation markers after stereotactic core needle biopsy. METHODS: 80 consecutive biopsies were performed at three breast centre sites. The markers included: HydroMARK(®) (Mammotome, Cincinnati, OH), MammoMARK™ (Mammotome, Cincinnati, OH), MammoStar™ (Mammotome, Cincinnati, OH) and SecurMark(®) (Hologic, Bedford, MA). Each marker was composed of a radiopaque core with a unique polymeric encasing component. Post-procedure mammograms were obtained and the degree of marker displacement was measured. RESULTS: MammoMARK™ exhibited the greatest mean net displacement, followed by HydroMARK(®), SecurMark(®) and MammoStar™ (13.9, 7.7, 5.8 and 4.7 mm, respectively), although these differences did not reach statistical significance (p = 0.398). 73% of the markers did not displace at all. However, in the 19 of 22 markers in which displacement occurred, the distance from the biopsy cavity was >10 mm. No statistically significant contributing factors to predict displacement were found. CONCLUSION: Newer generation biopsy markers perform comparably with one another. However, clinically significant and unpredictable marker displacement persists. Compared with multiple similar studies of older generation bare metallic markers, the overall displacement rate of newer generation markers seems to be lower, possibly owing to the use of polymeric embedding agents that self-expand within the biopsy cavity. ADVANCES IN KNOWLEDGE: This article compares the post-procedure displacement of breast biopsy markers, which have not been evaluated or discussed in detail since markers with polymeric embedding agents gained widespread use.