Cytologic diagnosis of lobular carcinoma of the breast: experience with 555 patients in the Rene Huguenin Cancer Center.

Background: Fine-needle aspiration generally produces results that are not as good for lobular carcinoma as the results for ductal carcinoma of the breast. In this study, the authors evaluated their team's performance in cytologic diagnosis of lobular carcinoma over 11 years and analyzed the reasons for diagnostic failure.

Methods: Cytologic findings were analyzed in 555 consecutive fine-needle cytopuncture specimens from women with palpable, invasive lobular carcinoma of the breast. The authors also examined the influence of the cytologist's experience, the clinical tumor size, the histologic subtype, and the histologic grade on diagnostic performance. All negative samples were re-examined, along with all samples that had been obtained during the last year of the study, to refine the morphologic description of lobular carcinoma.

Results: Malignancy was diagnosed in 68.8% of specimens overall. The individual pathologists diagnosed malignancy in from 44.4% to 81.1% of specimens, depending on their experience. Diagnostic performance was correlated with clinical tumor size, histologic grade, and histologic subtype, and correct diagnoses were significantly more frequent in pleomorphic subtypes than in "classic" types. Re-examination of all 32 negative specimens reduced the false-negative rate from 5.8% to 3.8%.

Conclusions: Despite the pitfalls associated with lobular carcinoma of the breast, fine-needle cytopuncture remains a useful diagnostic tool before treatment. Failures can be reduced through experience and by better knowledge of cytologic features.