Prevalence and Predictive Value of BI-RADS 3, 4, and 5 Lesions Detected on Breast MRI: Correlation with Study Indication.

RATIONALE AND OBJECTIVES: This study aims to determine the prevalence and predictive value of Breast Imaging Reporting and Data System (BI-RADS) 3, 4, and 5 findings on breast magnetic resonance imaging (MRI) and to evaluate the impact of study indication on the predictive value of BI-RADS categories. MATERIALS AND METHODS: This institutional review board approved, Health Insurance Portability and Accountability Act (HIPAA) compliant retrospective review of our breast MRI database from 2009 to 2011, of 5778 contrast-enhanced studies in 3360 patients was performed. At our institution, each breast receives an individual BI-RADS assessment. Breast MRI reports and electronic medical records were reviewed to obtain BI-RADS assessment, patient demographics, and outcomes. Univariate analysis was performed with Fisher exact and chi-square tests. RESULTS: A total of 9216 BI-RADS assessments were assigned during the study period: 7879 (85.5%) BI-RADS 1 and 2, 567 (6.2%) BI-RADS 3, 715 (7.8%) BI-RADS 4, and 55 (0.6%) BI-RADS 5 assessments. The frequency of BI-RADS 3, 4, and 5 assessments was higher in studies performed for diagnostic (7.8%, 14.6%, 1.6%, respectively) than screening (5.2%, 4.0%, 0.1%) indications (P < 0.01). A total of 663 BI-RADS 4 and 5 lesions were biopsied with 209 (31.5%) malignant and 454 (68.5%) benign outcomes. The overall cancer rate for BI-RADS 3 findings was 1.9% (11 of 567) with no difference observed by study indication (diagnostic, 1.6%; screening, 2.3%; P = 0.76). The positive predictive value (PPV2) of BI-RADS 4 and 5 was higher for diagnostic (29.1%, 154 of 530) than for screening (22.9%, 55 of 240) indications. CONCLUSIONS: Abnormal interpretation rates and PPV2 for MRIs performed for diagnostic indications are higher than for screening indications. Similar to mammography, breast MRI audits should be separated by study indication.

Risk of malignancy in palpable solid breast masses considered probably benign or low suspicion: implications for management.

OBJECTIVES: To determine whether solid palpable breast masses with benign sonographic features have less than 2% incidence of malignancy, allowing management by surveillance instead of biopsy. METHODS: With Institutional Review Board approval, sonography reports of palpable solid breast masses from January 1, 2006, to December 31, 2009, prospectively classified as probably benign (American College of Radiology Breast Imaging Reporting and Data System [BI-RADS] 3) or low suspicion (BI-RADS 4A) were reviewed. Category 4A lesions were included because many palpable benign-appearing masses at our institution are classified as 4A for palpability. The BI-RADS categories were correlated with outcome data, comprising tissue diagnosis, imaging stability for at least 24 months, or decrease/resolution during imaging surveillance. RESULTS: The study population included 440 lesions in 381 patients (mean age, 31.0 years; range, 15-68 years). A total of 161 lesions were prospectively classified as BI-RADS 3 and 279 as BI-RADS 4A. A total of 295 lesions (67%) had biopsy within 4.5 months of presentation, with 3 invasive malignancies; 145 of 440 lesions (33%) underwent surveillance. Forty-one lesions were considered benign for the following reasons: stability for at least 24 months (n = 28), benign tissue diagnosis during surveillance (n = 5), and decrease/resolution during follow-up (n = 8). The malignancy rate in lesions with adequate follow-up or biopsy was 3 of 336 (0.9%). All 3 malignancies occurred in women older than 40 years. CONCLUSIONS: The incidence of malignancy in palpable solid breast masses classified as BI-RADS 3 or 4A in this study was less than 2%. In young women, surveillance rather than biopsy is appropriate for BI-RADS 3 palpable lesions. Palpability does not merit a BI-RADS 4A classification in solid masses with otherwise benign-appearing morphologic features, particularly in young women.

Mammographic and Sonographic Features of Angiolipoma of the Breast.

The mammographic and sonographic appearance of angiolipomas of the breast is presented. This rare benign variant of lipoma usually presents as a painless breast mass. The imaging characteristics of angiolipomas of the breast are variable, overlapping with both other benign breast neoplasms and with malignancies. The most common mammographic appearance of angiolipomas of the breast in this series was an oval or round, isodense, circumscribed mass. The most common sonographic features were oval shape, circumscribed borders, and iso- to slight hyperechogenicity. These imaging features are nonspecific and biopsy is required for definitive diagnosis.

Sonographic Evaluation of Clinically Palpable Breast Cancers Invisible on Mammography.

The purpose of this study was to determine the utility of sonography in the evaluation of palpable breast cancers invisible on mammography. A retrospective review of the pathology department's database was used to identify patients with palpable breast cancers. Consecutive patients that had excision between January 1992 and September 1997 were included. Mammograms and breast ultrasounds were reviewed retrospectively and correlated with pathologic and surgical findings. During the study period 298 women presented with a palpable breast cancer for imaging at our institution. Of these, 38 cancers (12.8%) were not seen on mammography. In 32 patients where no mammographic abnormality was found, ultrasound was able to detect a mass corresponding to the area of clinical concern. Histologic tumor types included 30 invasive ductal carcinomas, 5 ductal carcinomas in situ, and 3 invasive lobular carcinomas. Mammographic density was mild with scattered fibroglandular densities in 2 (5%), heterogeneously dense in 12 (32%), and extremely dense in 24 (63%). Thirty-one masses (97%) were hypoechoic and 1 (3%) was echogenic. Lesion margins were irregular in 23 (72%), lobulated in 5 (16%), and well-circumscribed in 4 (12%). In this group of patients the combination of mammography and ultrasound of the mass demonstrated 99% of the palpable cancers. In patients presenting with a breast mass on physical examination in whom mammography fails to demonstrate an abnormality, supplemental ultrasound is helpful in most instances to further characterize the lesion.

Lactating Adenoma: Sonographic Features.

The lactating adenoma is a benign breast lesion occurring as a palpable mass in pregnant or lactating patients. The ultrasound characteristics of 15 lactating adenomas in 15 patients were reviewed retrospectively. Most of the lactating adenomas in this series (10 of 15) had one or more typically benign features such as circumscribed borders, smooth lobulations, or an echogenic pseudocapsule. The remaining five, however, had features typically associated with malignancy, including irregular, angulated, or ill-defined margins, or posterior acoustic shadowing.