Microvessel Density and Distribution in MRI-Detected Benign Breast Lesions
Jesse S Bond, Roberta M diFlorio-Alexander, Vincent A Memoli, Wendy A Wells, Jonathan D Marotti. Dartmouth-Hitchcock Medical Center, Lebanon, NH
Background: The majority of MRI-detected breast lesions are benign on biopsy, and therefore, many biopsies prove to be unnecessary. The aim of this study was to evaluate microvessel density (MVD) and distribution in benign breast lesions to better understand why they show increased MRI enhancement.
Design: The radiology database was retrospectively searched from 2005-2012 to identify all MRI-guided breast biopsies. 10 clustered apocrine cysts, 10 benign papillary lesions, 10 invasive ductal carcinomas (IDC) and 4 pseudoangiomatous stromal hyperplasia (PASH) cases were selected for immunohistochemical analysis with CD31 and CD105. MVD was quantified independently by two pathologists (JM and JB) evaluating identical fields on a multi-headed microscope at 200X magnification. Using the “hot-spot” technique, three areas of highest MVD in the center of each lesion, and in stroma away from each lesion excluding lobular epithelium, were chosen for vessel count. Interobserver correlation was calculated using linear regression analysis and comparison between lesional areas and stroma was analyzed by t-test. ANOVA was used to compare MVD among the lesions.
Results: Between 2005 and 2012, 235 MRI-guided biopsies were performed, of which 161 (69%) were benign. Overall correlation between pathologists was excellent (R2=0.91). Compared to normal stroma, mean CD31 MVD was increased in clustered apocrine cysts (33 vs. 14 p<0.0001), benign papillary lesions (63 vs. 19, p<0.001), and invasive ductal carcinoma (67 vs. 19, p<0.0001). Dense periductal vascular cuffing was seen in 90% of clustered apocrine cyst cases. Although not statistically significant, a trend towards higher MVD in PASH was seen (43 vs. 23). Mean CD105 MVD was higher in IDC (27.4) compared to benign papillary lesions (16.5) and clustered apocrine cysts (6.7), however, normalized lesion to stroma MVD ratio was not significantly different among benign lesions and IDC for CD31 (p=0.138) and CD105 (p=0.221). 90% of clustered apocrine cysts were enhancing foci (<5mm) or small masses < 9 mm.
Conclusions: MVD in MRI-detected benign breast lesions is increased compared to normal stroma, with most clustered apocrine cysts having a prominent periductal distribution similar to that previously reported in DCIS. Most clustered apocrine cysts were small enhancing foci or masses. Further studies are warranted to validate these findings, examine additional benign proliferative lesions, and to correlate with imaging to potentially identify predictive MRI features of benign lesions.
Monday, March 4, 2013 1:00 PM
Poster Session II # 31, Monday Afternoon