In view of the great variation in the size of epithelial cell nucleic in benign changes in the mammary gland, the cytologist is often faced with diagnostic difficulties. Clear differences in the size of the nucleic in aspiration biopsies from the mammary glands of pregnant women and those from the mammary glands of post-menopausal women seem to indicate that even in normal, unchanged mammary gland epithelia, the cell nucleic size varies in accordance with the hormonal situation and any functional changes that might have occurred.
To test these findings, the nuclear area of the mammary gland epithelia was compared in four groups consisting of 20 post-menopausal women, 20 sexually mature women, 20 gravid women and 20 women taking ovulation inhibitors.
In addition, we measured the nuclear area of tumour cell nuclei from solidly growing mammary carcinomas and their hybrid forms. The 40 patients with mammary carcinomas included 20 sexually mature women and 20 post-menopausal women.
A comparison of the size of the nuclei of normal epithelial cells revealed distinct differences in each group. The only exceptions were the sexually mature women and the women taking ovulation inhibitors, between whom there was no significant difference. The average nuclear area in post-menopausal women was 48
m
2, in sexually mature women 75
m
2, in pregnant women 118
m
2, and in women taking ovulation inhibitors 79
m
2.
The difference between the size of the nucleic in the tumour cells and those in normal mammary gland epithelia was significant in all groups. The average size of the tumour cell nuclei in sexually mature women was 185
m
2, and in post-menopausal women 170
m
2. A major difference between the two tumour groups was the noticeably larger range in the size of the nuclear area in the sexually mature women.
Key words Breast epithelia - Mammary carcinoma