Fine-needle aspiration of the breast: diagnoses and pitfalls. A review of 3545 cases.

Fine-needle aspiration is now a recognized diagnostic tool. In the past eight years we have studied 3545 aspirates from the breast, including both cystic and solid masses. All were prepared according to the method of Papanicalaou. The cellular findings are described and discussed. Abnormal cells were found in the aspirates from 90% of the 368 malignancies. Reliable criteria for diagnosis are emphasized and diagnostic pitfalls discussed. Aspiration biopsy was helpful in the management of all patients with breast lesions. The method is rapid, accurate, and essentially complication-free. It should be used with the idea of complementing, not competing with, routine histologic biopsy.