Needle core biopsy and open biopsy of breast lesions: Comparison of histologic results and expression of hormone receptors and Ki-67

Purpose: To compare histologic findings and immunohistochemical staining for steroid hormone receptors and the nuclear proliferation Ki-67 in needle core biopsies and specimens subsequently obtained at open breast biopsy. Material and Methods: 58 patients underwent ultrasound-guided percutaneous needle biopsy of breast lesions. 48 lesions were subsequently excised. Expression of hormone receptors was evaluated immunohistochemically by the number and staining intensity of cells (n = 35). Ki-67 expression was assessed semiquantitatively on the basis of the number of positive cells (n = 14). Results: 48 core biopsie specimens were diagnosed as carcinoma and 8 as benign lesions. One biopsy contained no tissue and another showed epithelial cells without nuclei; at open biopsy both these lesions were carcinomas. No complications occurred. Hormone receptor status was compared in 35 cases. All but estrogen-receptor-positive surgical specimens were associated with positive biopsy specimens, except one technically inadequate biopsy (97%). Progesterone receptor status agreed in 31 cases (89%). Two biopsy specimens were technically inadequate. Two biopsies were negative while the surgical specimens were positive. One tumor showed homogenous but weak expression whereas the other showed heterogenous expression. Ki-67 activity was analyzed in 14 cases and agreed in 13 (98%). Conclusions: Ultrasound-guided needle core biopsy is an accurate technique for evaluating breast lesions. In breast carcinomas, hormone receptor status and Ki-67 expression can be assessed with a high degree of accuracy.