[Clear cells of the endometrium: an indicator of estrogen level]

We examined 70 cases of curettage (24 in normal proliferative phase and 46 with endometrial hyperplasia) and determined the percentage of clear cells among all glandular cells. The number of clear cells was increased in endometrium with hyperplasia without atypia or with minimal atypia (Grade of the endometrial hyperplasia I-IV. Classification of Hendrickson and Kempson 1979). It decreased as the hyperplasia became more severe. Besides we noticed an increase of clear cells in late proliferative phase. The relation of clear cells to estrogen level has been discussed.