ObjectiveTo evaluate the prognostic significance of the Bethesda system's cytologic categories in patients with endometrial malignancy.MethodsPatients with biopsy or hysterectomy-proven endometrial malignancy and a Papanicolaou smear result reported using the Bethesda system within 1 year of diagnosis were identified through retrospective review of our computerized database.ResultsAfter introduction of the Bethesda system in our laboratory on November 1, 1992, until January 1, 1997, 112 eligible patients were identified (108 with crcinomas and four with carcinosarcomas). Patients with cytologic dianoses of malignancy (n= 17) were significantly more likely to hacve International Federation of Gynecology and Obstetrics (FIGO) grade 3 tumors and high-risk histology (serous, clear cell, and adenosquamous carcinoma and carcinosarcoma) than those with atypical glandular cells of uncertain significance (n= 33) or those with cytology not suspicious for malignancy (n= 63). Patients with malignant smears were also significantly more likely to have cervical extension, malignant peritoneal cytology, and FIGO stage II, III, or IV than those with atypical glandular cells of uncertain significance or those with cytology not suspicious for malignancy.ConclusionPapanicolaou smears obtained within 1 year of histologic diagnosis of endometrial malignancy and interpreted using the Bethesda system were suspicious for (atypical glandular cells of uncertain significance) or diagnostic of malignancy in nearly half of all cases (29 and 15%, respectively). Patients having malignant glandular cells were more likely to have poor prognostic pathologic finings.