Cytology of argyrophilic carcinoma of the breast.

Aspirations of breast lesions from 57 patients were studied by evaluating Grimelius-stained smears in order to determine the cytologic features of argyrophilic carcinoma and the reliability of argyrophilia as a characteristic of malignancy. The cytologic preparations were compared with histologic material. Sixteen benign lesions, 24 carcinomas correctly diagnosed by cytology and 5 carcinomas with technically inadequate smears were argyrophil negative. Five of 12 carcinomas with equivocal cytology were argyrophilic. There was perfect to case-to-case correlation between argyrophilia seen on histologic slides and on smears. The smears of the 5 argyrophilic carcinomas and 2 of the argyrophil-negative carcinomas with equivocal cytology shared features in common not seen in the other 50 smears: elongated cells with eccentric, round-to-oval nuclei and granular or opaque cytoplasm. These features can alert the pathologist to the possibility of malignancy in smears with equivocal cytology. A positive stain for argyrophilia will further increase the index of suspicion.