Apocrine cells in breast cyst fluid and their relationship to cyst type: a morphometric study

The morphology of apocrine cells exfoliated in breast cyst fluid (BCF) was studied in 78 BCF samples obtained from 39 premenopausal patients with gross cystic disease who were bearing two simultaneously aspirated cysts. 57/78 samples showed cell clusters suitable for computer-assisted cytometry. This was performed on 5820 cells using a Leitz Texture Analysis System (TAS). We measured the surface areas of cytoplasm, nucleus and nucleolus; we also calculated the nuclear/cytoplasmic (N/C), nuclear/nucleolar (N/n) ratios and the nuclear roundness factor (RF). Cysts were divided according to the cationic pattern of BCF: Type I, K+/Na+ greater than 1.5; Type II, K+/Na+ less than 0.66. The cytometric analysis was made on 47 samples of Type I and 10 samples of Type II. At the light microscope, no difference was apparent between the apocrine cells coming from Type I or Type II cysts. Cytometric measurements showed significant differences for the apocrine cells aspirated from Type I vs. Type II cysts for the mean cytoplasmic area (97.13 +/- 24.28 S.D. mu2 vs. 59.66 +/- 14.90 S.D. mu2, respectively) and the mean nucleolar area (4.35 +/- 0.99 S.D. mu2 vs. 2.75 +/- 0.71 S.D. mu2, respectively). Our data do not allow the inference of apocrine changes in the epithelium lining the cysts simply from the cationic pattern of BCF. The significantly wider cytoplasm and nucleoli of the apocrine cells aspirated from Type I cysts could reflect different functional stages of these particular cells.