Accuracy of FNA Versus CNB of Abnormal Axillary Lymph Nodes in Setting of Invasive Breast Cancer

To compare accuracy of ultrasound guided fine needle aspiration (FNA) to core needle biopsy (CNB) of ultrasound detected abnormal axillary lymph nodes in patients with newly diagnosed invasive breast cancer or suspected invasive breast cancer. Hypothesis: FNA and CNB have equivalent diagnostic accuracies In order to prove our hypothesis, we will perform FNA and CNB on the same lymph node in each consented patient. The two samples will be evaluated separately by different pathologists blinded to the material in the other sample. The results of the biopsies will be compared to the gold standard (lymph node excision).