Atypical glandular cells of undetermined significance favor endometrial origin. Criteria for separating low grade endometrial adenocarcinoma from benign endometrial lesions

OBJECTIVE: To evaluate cytologic criteria for separating atypical glandular cells of undetermined significance favor endometrial origin (AGUS-EM), on Papanicolaou-stained (Pap) smears into favor benign and favor malignant categories. STUDY DESIGN: All patients who had a Pap smear diagnosis of AGUS-EM, not further qualified, followed by tissue follow-up were identified from the surgical pathology and cytopathology files from January 1992 through December 1996. The Pap smears were scored blindly for the presence or absence of 40 cytologic criteria, and univariate analysis was performed to determine which criteria were most indicative of malignancy by tissue follow-up. RESULTS: The presence of an atrophic smear, nuclear size greater than twice that of an intermediate cell nucleus and absence of clusters with irregular borders were highly indicative of adenocarcinoma, although other criteria were also helpful in identifying malignancy. CONCLUSION: There are no combinations of cytologic criteria that definitely separate AGUS-EM cases into those with benign or malignant findings on follow-up. However, some isolated criteria were useful in the differential diagnosis in a table: see text] significant number of cases.