Aspiration cytology of tubular breast carcinoma.

The cytologic features in smears of fine needle aspirates from 34 tubular breast carcinomas were studied. Uniform and bland epithelium in cohesive clusters dominated all specimens; two-thirds also showed some degree of cellular dissociation. Characteristic (but not quite pathognomonic) angular epithelial clusters with a tubular structure occurred in about 50% of the smears. Sparsely occurring atypical nuclei and/or cytoplasmic vacuoles, similar to those seen in lobular cancer, were found in half of the cases. Although a lack of myoepithelial cells was apparent in the majority of the smears, one-fourth of them showed a quite prominent myoepithelial component. Various combinations of atypical features resulted in a picture that was considered diagnostic of malignancy in 50% of the cases; the remaining specimens showed less pronounced atypia. Other pitfalls associated with the cytologic diagnosis of tubular carcinoma are discussed, and the importance of basing the management of small breast lesions on the mammographic as well as on the cytologic findings is emphasized.