Characterization of cell clusters in smears from normal endometrium, endometrial hyperplasia and well differentiated adenocarcinoma

Endometrial smears from 22 cases of well differentiated adenocarcinoma, 19 of adenomatous hyperplasia, and 25 of normal endometrium were examined cytologically to establish criteria for the screening of endometrial lesions, and for the differential diagnosis of well differentiated adenocarcinoma and adenomatous hyperplasia. As it had been difficult to evaluate individual cells in the larger cell clusters accurately, the clusters were classified into several groups according to their shape, and the proportions of these groups on each smear were calculated. The presence of other cytological findings, such as small clusters of atypical cells, squamous metaplasia, inclusion of inflammatory cells, and necrotic background, was also evaluated. The large cell clusters could be classified into eight groups, namely, NGSES, sheet-shaped, tube-shaped, dilated gland, irregularly ragged, papillary, compiled glands, and branch-shaped. The former four groups appeared to be normal, while the latter four were seen in the smears from hyperplasia or carcinoma, and hence thought to be abnormal. We consider the following criteria to be important in the screening of endometrial smears. 1) Lesions greater than hyperplasia are suspected when the smear contains more than 20% of abnormal clusters. 2) Well differentiated carcinoma is suspected when the smear contains more than 70% of abnormal clusters. 3) The presence of irregularly ragged, dilated-gland, or papillary clusters could be evidence of lesions greater than hyperplasia. 4) Branch-shaped clusters are specific to well differentiated adenocarcinoma. 5) When well differentiated adenocarcinoma is suspected, the presence of small clusters of atpical cells, squamous metaplasia, inclusion of inflammatory cells, or necrotic background on the smear could provide corroboration.