Nuclear grooves in fine needle aspiration (FNA) biopsies of breast lesions.

The present study was undertaken to evaluate the significance of grooved nuclei as an additional diagnostic criterion for primary breast carcinoma as well as their association with tumor grade in cytologic material obtained by fine needle aspiration (FNA). Cytologic slides of 105 cases of breast carcinoma (89 ductal, 10 lobular, 3 medullary, 3 mucinous) and 39 cases of benign lesions were reviewed. Histologic confirmation was obtained in all cases. In each case the number of grooved nuclei per 200 well-preserved cells per slide was recorded. Nuclear grooves were found in 62% (65/105) of the malignant and in 36% (14/39) of the benign lesions. This cytomorphologic feature was observed in all histologic types of breast carcinoma. Furthermore, nuclear grooves were present in all grades of ductal carcinoma, and at about the same frequency. Our findings indicate that in the mammary gland nuclear grooving cannot be considered as a criterion of malignancy, and is not helpful either in differentiating the various histologic types or in grading breast tumors in FNA preparations.