Objective. To investigate clinical outcomes of stage IA uterine papillary serous (UPSC) and clear cell carcinoma (CC) arising from or associated with a polyp. Methods. From 1995 to 2011, we identified 51 cases of stage IA UPSC (67%), CC (8%) or mixed histology (26%) endometrial cancer. Of these, 32 had disease confined to polyp (seven with no residual disease after hysterectomy), 14 had surface spread, 1 had myometrial invasion (MMI) and 4 had both. The majority of patients did not receive adjuvant therapy (80%). Patients given adjuvant treatment (either platinum-based chemotherapy alone, radiation alone, or a combination of the two) had incomplete staging or abnormal cytology. Results. At mean follow-up of 58.3 months, only 4 patients had progressed, via pelvic adenopathy, carcinomatosis or both. There were no vaginal cuff recurrences. Kaplan-Meier 5 year estimates were pelvic control of 92.1%, disease-free survival 93% and OS 80.6%. Only 9% (3/32) of cases confined to polyp progressed. One responded to salvage chemoradiation, but two died despite salvage. Only 5% (1/19) of cases with surface and MMI progressed. On univariate analysis, only MMI and abnormal/positive cytology were significantly associated with increased pelvic recurrence (MMI p = 0.0059, cytology p = 0.0036) and worse DFS (MMI p = 0.0018, cytology p = 0.0054). Two patients given adjuvant treatment developed new gynecologic malignancies. Conclusion. In our study, patients with limited UPSC/CC disease involving a polyp who have complete workup did well without adjuvant therapy, with recurrence rates similar to UPSC/CC stage IA disease. Late and extensive pelvic relapses may occur in the few who do relapse. (C) 2013 Elsevier Inc. All rights reserved.