The Histopathologic Findings of Magnetic Resonance Imaging Enhancement of Breast Lesions with Histologically Mass-Negative Lesion: A Single Institution Experience.
LaKeta Monhollen, Prasanna Kumar, Rameela Chandrasekhar, Gregory Wilding, Thaer Khoury. Roswell Park Cancer Institute, Buffalo, NY
Background: Magnetic resonance imaging (MRI) is increasingly being used to detect breast lesions for patients with high risk or as part of staging with varying results. The histologically non-mass lesions that are enhanced by MRI have had little attention. The objective of this study is to review the histologic findings on these biopsies.
Design: One hundred-sixty five cases were selected from the archives at Roswell Park Cancer Institute between 2001 and 2010. We defined histologically mass lesion as carcinoma (in situ or invasive), fibroadenoma, papilloma or radial scar. All other lesions were considered mass-negative lesions. These lesions included stromal fibrosis, pseudoangiomatous stromal hyperplasia (PASH), inflammation, sclerosing adenosis, apocrine metaplasia, duct ectasia and ductal hyperplasia. One or more histologic entity could be present in one biopsy. These lesions were graded from 0 to 3, based on the degree of involvement; ≥1 was considered present. Statistical analyses to assess the significance of the difference between two correlated proportions based on the same sample were performed using the exact McNemar's test.
Results: A total of 80 (48.5%) cases had mass lesions that would account for enhancement on MRI, 35 (21.2%) carcinoma and 45 (27.3%) were other mass lesions including radial scar, papilloma or adenoma. The remaining 85 (51.5%) cases, classified as mass-negative, had stromal fibrosis in 84.7%, PASH in 50.6%, ductal hyperplasia in 47.1%, sclerosing adenosis in 37.7%, apocrine metaplasia in 34.1%, duct ectasia in 32.9% and inflammation in 32.9%. Stroma fibrosis was significantly more common than all other findings (p-value <0.0001), while PASH was significantly more common than duct ectasia and inflammation only (p value 0.03 each).
Conclusions: Our results indicate that the pathologist should expect that fibrosis and PASH to be the most common findings in histologically mass-negative enhanced-lesions by MRI. It is unclear why these changes produce MRI enhancement. More studies to explore the reason are needed.
Tuesday, March 1, 2011 9:30 AM
Poster Session III # 42, Tuesday Morning