Cytologic diagnosis of breast carcinoma with nipple discharge: special significance of the spherical cell cluster.

In order to investigate the cytologic characteristics of breast carcinoma in nipple discharge, 190 histologically proven cases of various breast lesions from 2,723 samples of nipple discharge were studied. The general criteria of malignancy as described for other organs applied also to the breast carcinoma cells. However, the breast carcinoma cells were generally smaller and less pleomorphic than those arising from other organs. In addition to the malignant features of individual tumor cells, the presence of a spherical cell cluster with a smooth rim was also an important finding suggestive of malignancy. The diagnostic rate of breast carcinoma increased significantly when the 190 cases were reexamined on the basis of the findings of this study.