Because cellular atypia is often limited in endometrial hyperplasia and well-differentiated endometrial adenocarcinoma (WHO Grade 1 adenocarcinoma), diagnostic criteria for endometrial cytology have not been fully established. New diagnostic criteria based on the composition and architecture of tissue fragments (cytoarchitecture) in the smears were used in the present study. Cytologic features are of less importance because the distinction between endometrial hyperplasia and Grade 1 adenocarcinoma relies more on architectural features than cellular changes. Cell clumps of various size are usually collected abundantly with cytologic material using a disposable scraping device and it was noticed that those cell clumps reflected the histologic architecture. The purpose of the current study was to determine the form of the cytoarchitecture that reflects the histologic structure and to examine the cellular features in endometrial hyperplasia and Grade 1 adenocarcinoma.
The frequency of each type of cell clump (tube or sheet-shaped pattern, dilated or branched pattern, irregular protrusion, and papillotubular pattern) were obtained from 49 cases of normal proliferative endometrium (NPE) (patient age range, 28-51 yrs; average age, 39.9 yrs), 63 cases of endometrial hyperplasia without atypia (EH) (patient age range, 35-65 yrs; average age, 47.7 yrs), 13 cases of endometrial hyperplasia with atypia (AEH) (patient age range 47-65 yrs; average age, 53.8 yrs), and 49 cases of Grade 1 adenocarcinoma (patient age range, 42-73 yrs; average age, 58.9 yrs).
Certain characteristics of the cytoarchitecture were observed. In the NPE, cell clumps with a tube or sheet-shaped pattern were found in 97.5% of cases. In the EH, cell clumps with a dilated or branched pattern were found in 34.9% of cases. In the Grade 1 adenocarcinoma, cell clumps with irregular protrusions were found in 61.8% cases, whereas a papillotubular pattern was present in 29.7% of cases.
The results of the current study revealed that cytoarchitectural criteria appear to be more useful for the cytologic assessment of endometrial lesions, especially for the diagnosis of endometrial hyperplasia and Grade 1 adenocarcinoma.