Introduction/Background Studies on atypical endometrial hyperplasia (AEH) consistently reported high risk for the coexistence of endometrial cancer (EC) or progression to EC. On the other hand, the final diagnosis may turn out to be benign pathology (hyperplasia without atypia or normal endometrium) after hysterectomy for AEH. The purpose of this study was to determine the rates of under- and over-estimation compared to the final pathology after hysterectomy for AEH and to evaluate the predictive role of endometrial thickness

Methodology We retrospectively reviewed the medical records of 94 patients with AEH at two referral hospitals in Ankara between 2015 and 2020. 60 of them underwent a hysterectomy within 6 months after the index biopsy . Data were extracted for age, menopausal status, tamoxifen use and endometrial thickness . Of these 60 patients, 57 of whom we could reach the final pathology result were evaluated

Results Among patients who underwent hysterectomy due to a diagnosis of atypical hyperplasia, 23 cases (40,35%) were underestimated (cancer),11 cases (19,29%) were equivalent and 23 cases (40.35%) were overestimated .There was no difference among these groups in endometrial thickness by transvaginal ultrasonography .

Conclusion Diagnosis of atypical endometrial hyperplasia by endometrial biopsy may often resulted in under- or over-estimation. As there is neither a reliable clinical parameter nor imaging feature to distinguish between these groups, hysterectomy is still the best treatment option for these patients .