in the breast parenchyma during the menstrual cycle [4][5][6]. Estrogen has been shown to exert a histamine-like effect that causes an increase in microvascular permeability and vasodilation, and progesterone exerts a mitogenic effect that may increase metabolic activity, also resulting in an increase in perfusion [7,8].The detection of malignancy at MRI is based on the fact that tumors show neovascularity, with increased blood flow and increased vascular leakiness, and relies on the differential enhancement between neoplastic tissue and normal breast parenchyma [9][10][11][12][13]. It has been postulated that benign enhancement may obscure the detection of small cancers by masking this difference. In addition, although MRI is very sensitive for the detection of malignancy, specificity is somewhat Wo m e n's I m ag i ng • O r ig i n a l R e s e a rc h CMEThis article is available for CME credit. See www.arrs.org for more information. 2011; 196:218-224 0361-803X/11/1961-218 © American Roentgen Ray Society B ackground parenchymal enhancement on breast MRI refers to the normal enhancement of the patient's fibroglandular tissue seen on the first contrast-enhanced image. Background enhancement is due to the increase in T1 relaxation of tissue that occurs after gadolinium administration, and the degree of enhancement is directly related to vascular supply and permeability. Background parenchymal enhancement is thought to be related to endogenous hormone status and fluctuates with the menstrual cycle, being highest during weeks 1 and 4 and lowest during week 2 [1,2]. It increases in postmenopausal women receiving hormone replacement therapy (HRT) [3]. Changes in background parenchymal enhancement likely correlate to hormone-dependent histopathologic changes that occur Keywords: background parenchymal enhancement, BI-RADS category 3, MRI breast biopsy rate, screening breast MRI DOI:10.2214/AJR.10.4550 AJRReceived March 3, 2010; accepted after revision June 6, 2010. W O M E N ' S I M A G I N GOBJECTIVE. Background parenchymal enhancement on breast MRI refers to normal enhancement of the patient's fibroglandular tissue. The aim of this study was to determine the effect of background parenchymal enhancement on short-interval follow-up, biopsy, and cancer detection rate on baseline screening MRI in a high-risk group.MATERIALS AND METHODS. Two hundred fifty baseline high-risk screening MRI examinations were reviewed. For each, the background parenchymal enhancement pattern was recorded (minimal, ≤ 25%; mild, 26-50%; moderate, 51-75%; and marked, > 75%), as were BI-RADS category, biopsy rate, and final pathology result. Results were compared for each enhancement category.RESULTS. Of the 250 MRI examinations, 24.8% showed minimal enhancement; 34%, mild; 24%, moderate; and 17.2%, marked enhancement. Women with minimal enhancement had a significantly higher number of BI-RADS categories 1 and 2 examinations (64.5%) than women with mild (38.8%), moderate (40%), or marked (25.6%) enhancement. The BI-RADS category 3 rate was 43....

Background The surgical management of breast intraductal papilloma without atypia (IDP) identified at core needle biopsy (CNB) is controversial. We assessed the rate of upgrade to carcinoma at surgical excision, and identified parameters predictive of upgrade. Methods We identified women with CNB diagnosis of intraductal papilloma without atypia or carcinoma at our center between 2003 and 2013. Radiologic-pathologic concordance was assessed for all cases, and discordant cases were excluded. We correlated the radiologic and clinicopathologic features of patients with CNB diagnosis of IDP with upgrade to carcinoma at surgical excision. Results Our study population consists of 189 women with 196 IDPs; 166 women (171 IDPs) underwent excision. The upgrade rate was 2.3% (4/171). The upgrade lesions were 2 invasive lobular carcinomas and 2 cases of ductal carcinoma in situ (DCIS). One case of DCIS involved the residual IDP, whereas the other 3 carcinomas were ≥8 mm away. Twenty-four women (25 IDPs) did not undergo excision, and had stable imaging at follow-up (median of 23.5 months). Conclusions The upgrade rate at excision of IDP diagnosed at CNB with radiologic-pathologic concordance is 2.3%. Our findings suggest that observation is appropriate for patients with radiologic-pathologic concordant CNB yielding IDP, regardless of its size.

We found that breast MRI screening of women with only a personal history of breast cancer was clinically valuable finding malignancies in 12%, with a reasonable biopsy rate (PPV, 39%).

Triple-negative (TN) breast cancers, which are associated with a more aggressive clinical course and poorer prognosis, often present with benign imaging features on mammography and ultrasound. The purpose of this study was to compare the magnetic resonance imaging features of TN breast cancers with estrogen (ER) and progesterone (PR) positive, human epidermal growth factor receptor (HER2) negative cancers. Retrospective review identified 140 patients with TN breast cancer who underwent a preoperative breast MRI between 2003 and 2008. Comparison was made to 181 patients with ER+/PR+/HER2- cancer. Breast MRIs were independently reviewed by two radiologists blinded to the pathology. Discrepancies were resolved by a third radiologist. TN cancers presented with a larger tumor size (p = 0.002), higher histologic grade (<0.001), and were more likely to be unifocal (p = 0.018) compared with ER+/PR+/HER2- tumors. MRI features associated with TN tumors included mass enhancement (p = 0.026), areas of intratumoral high T2 signal intensity (p < 0.001), lobulated shape (p < 0.001), rim enhancement (p < 0.001), and smooth margins (p = 0.005). Among the TN tumors with marked necrosis, 26% showed a large central acellular zone of necrosis.

AIMS Surgical excision of all benign vascular lesions of the breast identified by core needle biopsy has been recommended in the past to rule out a more serious lesion. In this study we investigated the clinical, radiologic, and pathologic findings in patients diagnosed with a benign vascular lesion at our institution to assess whether excision may be spared for lesions without atypia. METHODS AND RESULTS We searched the electronic medical record for patients with a vascular lesion of the breast diagnosed between 2000 and 2015. The study population consisted of 84 patients, 83 females and 1 male. The index diagnoses included 76 benign vascular lesions, 5 vascular lesions with cytologic atypia, and 3 angiosarcomas. A radiologist reviewed all pre and post-biopsy imaging studies; all cases had concordant radiologic and pathologic findings. Based on radiologic and histologic correlation, the vascular lesion accounted for the radiologic target in 40 (48%) cases and was deemed an incidental finding in 44 (52%). 7 of 32 (22%) targeted and 10 of 44 (23%) incidental benign vascular lesions underwent surgical excision; there were no upgrades at excision. No recurrences or clinical events were observed in patients with a targeted or incidental benign vascular lesion with a median followup of 39 months and 40.6 months, respectively. CONCLUSION Our data suggest that benign vascular lesions diagnosed on core biopsy with concordant radiologic and pathologic findings do not warrant surgical excision.