Endometrial cytologic findings in tamoxifen-treated breast cancer patients.

Objective To describe the endometrial cytologic findings in tamoxifen (TAM)-treated patients and evaluate the clinical significance of these findings. Study Design A total of 1,739 endometrial cytologic samples were obtained from 203 breast cancer patients with TAM treatment using an endocyte device. Histologic examinations were recommended for the 23 endometrial cytologic samples (18 initial and 5 follow-up endometrial cytologic samples). These 23 samples were cytopathologically reviewed. Results A large nuclear dimension and anisokaryosis of the endometrial glandular cells were found in the 23 endometrial cytologic samples. All patients were amenorrheic and postmenopausal except for 3 premenopausal women with endometrial cancer. The subsequent histologic examinations showed 3 atrophic endometria, 3 cystic atrophies, 11 endometrial polyps and 6 endometrial cancers. The tumor diathesis and atypical features of cell aggregates, such as a loss of polarity and severe piling up of nuclei, were seen in the cytologic samples of the endometrial cancers but were not found in those with benign conditions. Conclusion A large nuclear dimension and anisokaryosis of the glandular cells were sometimes found in endometrial cytologic samples from the TAM-treated patients. The atypical characteristics of the cell aggregates with these types of cellular atypia are useful for the cytologic assessment of malignancy.