Microvessel density is higher in invasive micropapillary carcinoma than in tubular carcinoma of the breast

Angiogenesis is required for tumor growth and progression and has been correlated with metastasis in many malignancies. Micropapillary carcinoma of the breast is a rare type of invasive breast carcinoma that is notorious for its high frequency of metastasis. In contrast, invasive tubular carcinoma of the breast rarely metastasizes. This study compares microvessel density (MVD) in these two types of invasive breast carcinomas, to understand the differences in their metastatic potential. Methods: Vessels were visualized by immunohistochemical staining with anti-CD34 monoclonal antibody (Immunotech) on formalin-fixed, paraffin-embedded archival tissue. Consecutive cases of micropapillary carcinomas (21) and tubular carcinomas (20) were included. For each case, microvessels were counted from 5 most vascular non-overlapping fields (20x objective and 10x ocular, Nikon) in a section. The averages of the 5 counts were used for statistic analyses. Results: Of the 21 micropapillary carcinoma cases. 14 had lymph node(s) for histological evaluation and 11 of them were positive. Of the 20 tubular carcinomas. 4 cases had lymph node (s) and none were positive. The MVD of micropapillary carcinoma ranged from 38 to 194 (mean, 88.5137.2). while in tubular carcinoma it was from 30 to 128 (mean, 59.9±22.0). The difference was statistically significant (p<0.01). Conclusion: MVD is significantly higher in invasive micropapillar carcinoma than in tubular carcinoma, suggesting that angiogenesis may play an important role in metastasis of micropapillary carcinoma.