Benign and malignant papillary lesions of the breast. A cytomorphologic study.

Fine-needle aspiration cytology of benign and malignant papillary lesions of the breast has been infrequently described. To define the cytologic features of benign and malignant papillary breast lesions better, the authors retrospectively reviewed the fine-needle aspiration cytology of five cases of histologically proven intracystic papillary carcinoma (IPC) and six cases of histologically proven papilloma. Clinical information was obtained from the medical records in each case. Intracystic papillary carcinoma tended to present as a larger tumor (average, 5 cm) in older women (average, 65.4 years). Papilloma, however, tended to present as a smaller tumor (average, 1.5 cm) in younger women (average, 43 years). Eighty percent of the IPC cases (4/5) and 50% of the papilloma cases (3/6) yielded highly cellular aspirates with complex vascular papillae and single columnar cells. Macrophages were a constant feature of IPC and were present in all but one case of papilloma. Although cellular atypia was not a prominent feature in either IPC or papilloma, moderate atypia was noted in one case of IPC and two cases of papilloma. Severe atypia was noted in a single case of IPC. Although IPC tended to yield a harvest with higher cellularity and single intact cells, no single feature or constellation of findings was consistently reliable in distinguishing IPC from papilloma. The authors found that papillary lesions of the breast demonstrate a distinct cytomorphology characterized by complex vascular papillae, columnar cells, and macrophages. They concluded, however, that, in the absence of overt cytologic malignancy, distinguishing between benign and malignant papillary breast lesions is difficult, if not impossible.