CYTOLOGIC DIAGNOSIS OF DUCTAL VERSUS LOBULAR CARCINOMA OF THE BREAST

OBJECTIVE: To determine the value of cytology in the differential diag nosis of ductal versus lobular carcinoma of the breast. STUDY DESIGN: In this study we examined 11 cytologic parameters in fine needle aspir ation (FNA) cytology specimens from 52 patients who underwent surgery and had subsequent histologic diagnoses. Eighty-eight percent (46 case s) were infiltrating ductal carcinoma, and 12% (6 cases) were invasive lobular carcinoma. RESULTS: Of the 11 cytologic parameters only chrom atin pattern (P < .0001), nuclear size (P < .004) and overall cell siz e (P < .004) showed statistically significant differences between the two groups. Nuclear chromatin was coarsely granular only in cases of d uctal carcinoma, while fine granularity could be seen in both ductal a nd lobular tumors. An automated morphometric system was used to determ ine the nuclear and overall cell size. The granularity of nuclear chro matin in ductal carcinoma cells did not correlate significantly with n uclear and overall cell size; therefore, they should be considered ind ependent cytologic parameters. CONCLUSION: The cytologic differential diagnosis of ductal versus lobular carcinoma is difficult; based on th is study, the presence of coarsely granular chromatin, nuclear size >4 4 mu m(2) and cell size > 82 mu m(2) are the only features diagnostic of ductal versus lobular carcinoma.