Utility of ultrasound and fine-needle aspiration biopsy of the axilla in the assessment of invasive lobular carcinoma of the breast

Background The unique growth pattern of invasive lobular carcinoma (ILC) poses a challenge for preoperative assessment of disease extent within the breast. Whether it similarly limits lymph node staging by ultrasound (US) and fine-needle aspiration (FNA) biopsy was the subject of the current study. Methods A total of 217 patients with ILC who underwent axillary US were reviewed. FNA biopsy was performed when US findings were suspicious or indeterminate. Findings were compared to literature reports of US in invasive ductal carcinoma (IDC) patients. Results Axillary US was negative in 137 patients (63%) and suspicious or indeterminate in 80 patients (37%). FNA biopsy was positive in 62% (47/76 patients). Preoperative US and FNA biopsy identified 43 of 111 (39%) node-positive patients. Sensitivity of US with FNA biopsy correlated with primary tumor and nodal metastasis size. Similar results were seen in IDC populations. Conclusion US with FNA biopsy appears to be similarly useful in axillary staging of ILC and IDC patients.