Introduction: Outpatient hysteroscopy permits direct visualisation of the endometrial cavity and is widely used in the investigation of abnormal uterine bleeding and postmenopausal bleeding. Endometrial biopsy is frequently performed during the same consultation, including when the hysteroscopic appearance is documented as normal. The additional diagnostic yield of routine biopsy in this setting remains clinically relevant, particularly given the possibility of inadequate sampling and additional procedural discomfort.
Objective: To determine the frequency of endometrial hyperplasia with atypia or carcinoma identified by endometrial sampling following a normal outpatient hysteroscopic impression, and to describe the histological yield and rate of insufficient sampling in this group.
Methods: We conducted a retrospective cohort study of patients attending a consultant-led outpatient hysteroscopy clinic at The Coombe Hospital, Dublin, between January and December 2024. Patients referred for assessment of abnormal uterine bleeding, postmenopausal bleeding, increased endometrial thickness or related indications were included. Hysteroscopic findings were classified according to the operating clinician's documented hysteroscopic impression. The primary outcome was histologically confirmed endometrial hyperplasia with atypia or endometrial carcinoma following a normal hysteroscopic impression. Histological samples were classified as normal, insufficient/non-diagnostic, or significant pathology.
Results: Of 709 patients attending the clinic during the study period, 442 were eligible for inclusion, and 267 were excluded. Hysteroscopy was performed in 358/442 (81.0%) patients. A good or excellent hysteroscopic view was documented in 327/358 (91.3%). The operating clinician documented a normal hysteroscopic impression in 207/358 (57.8%) patients. Among these 207 patients, 196 (94.7%) had a documented histology report. Of these, 171 (87.2%) had normal histology and 25 (12.8%) had an insufficient sample. No case of endometrial hyperplasia with atypia or carcinoma was identified among the 171 patients with diagnostic histology following a normal hysteroscopic impression.
Conclusion: In this retrospective cohort, no atypical hyperplasia or endometrial carcinoma was identified among patients with a normal outpatient hysteroscopic impression and diagnostic histology. More than one in eight histology reports in this subgroup was insufficient. These findings suggest that routine biopsy following a normal hysteroscopic impression may have limited additional diagnostic yield in appropriately selected patients. Prospective studies with predefined risk stratification and systematic follow-up are warranted to evaluate selective rather than routine endometrial sampling.