[330] Spectrum of Pathologic Findings in Magnetic Resonance Imaging (MRI)-Guided Breast Core Biopsies

W Zeng, MK Sidawy. Georgetown University Hospital, Washington, DC

Background: Breast MRI has been increasingly used in screening high-risk women, and evaluating the ipsilateral and contralateral breasts of women with a newly diagnosed breast cancer. Breast MRI is believed to benefit patients by detecting cancers that may be missed by mammography. However, the increased MRI sensitivity may be associated with a low speficity. This study evaluates the pathologic outcome of MRI-guided breast core biopsies in our institution.
Design: 152 MRI-guided breast biopsies were performed by two experienced radiologists over a 27 month period (5/06-8/08). Abnormal MRI findings included avid, linear, clumped or asymmetric enhancement, and enhancing distortion. The biopsy results were analyzed against the patients' personal and family history of breast cancer, and the biopsy side (ipsilateral vs. contralateral to a diagnosed cancer). Fisher's exact test was used with results considered statistically significant if the p-value was <0.05.
Results: Carcinoma (invasive or in situ) was detected in 14.47% (22/152) patients.

History	H/O breast cancer	H/O ADH	Family H/O breast cancer	No H/O of breast cancer	Total
No. of cases	86	4	30	32	152
Positive MRI bx (%)	15 (17.44%)	0 (0%)	1 (3.45%)	6 (18.75%)	22 (14.47%)

The above table summarizes the rate of malignancy in different groups based on history. The malignancy rate was similar between the group with a history of breast carcinoma and the group without a personal or family history of breast cancer (17.44% vs. 18.75%). Women with a diagnosed breast carcinoma had a higher malignancy rate in the ipsilateral vs. the contralateral breast (11/31 versus 4/38, p=0.013). - Atypical changes were detected in 12/152 cases (7.89%): 9 atypical ductal /lobular hyperplasia (ADH/ALH), 2 ADH bordering on ductal carcinoma in situ (DCIS), and 1 atypical apocrine adenosis. F/U was available in 3 cases. Two ADH bordering on DCIS correlated with DCIS and usual ductal hyperplasia, respectively. One ADH revealed DCIS in subsequent excision. - Benign proliferative changes were detected in 14 cases (9.21%): florid ductal hyperplasia (4), fibroadenoma (7) and papilloma (3). - Nonproliferative fibrocystic changes were detected in 89 cases (58.55%) - Unremarkable breast parenchyma was diagnosed in 15 cases (9.87%).
Conclusions: MRI enhanced breast lesions show a wide spectrum of pathologic findings ranging from invasive carcinoma to unremarkable breast parenchyma. Carcinoma and atypical changes were detected in 22 and 12/152 biopsies, respectively. The remaining 118 cases (77.6 %) were benign.
Category: Breast

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 27, Wednesday Afternoon