Accuracy of hysteroscopy in predicting histopathology of endometrium in 1500 women.

STUDY OBJECTIVE: To estimate the accuracy of hysteroscopy in predicting endometrial histopathology.

DESIGN: Retrospective analysis (Canadian Task Force classification II-2).

SETTING: Public hospital.

PATIENTS: One thousand five hundred women undergoing diagnostic hysteroscopy for suspected endometrial pathology, mostly because of abnormal uterine bleeding.

INTERVENTIONS: Hysteroscopy and endometrial biopsy.

MEASUREMENTS AND MAIN RESULTS: Hysteroscopy imaging was matched with histology. Functional, dysfunctional, and atrophic endometrium were considered normal findings; endometritis, endometrial polyps, hyperplasia, and carcinomas were considered abnormal. Sensitivity, specificity, and negative (NPV) and positive (PPV) predictive values of hysteroscopy in detecting normal or abnormal endometrium were calculated. These figures were defined to assess hysteroscopic accuracy in estimating pathologic conditions. Histology showed normal endometrium in 927 patients. Endometritis, polyps, hyperplasia, and malignancies were found in 21, 265, 185, and 102 patients, respectively. Hysteroscopy showed sensitivity, specificity, NPV, and PPV of 94.2%, 88.8%, 96.3%, and 83.1%, respectively, in predicting normal or abnormal histopathology of endometrium. Highest accuracy was in diagnosing endometrial polyps, with sensitivity, specificity, NPV, and PPV of 95.3%, 95.4%, 98.9%, and 81.7%, respectively; the worst result was in estimating hyperplasia, with respective figures of 70%, 91.6%, 94.3%, and 60.6%. All failures of hysteroscopic assessment resulted from poor visualization of the uterine cavity or from underestimation or overestimation of irregularly shaped endometrium.

CONCLUSION: Hysteroscopy was accurate in distinguishing between normal and abnormal endometrium. Nevertheless, better knowledge of relationship between hysteroscopic imaging and pathophysiologic states of endometrium is necessary to improve its accuracy. Endometrial sampling is recommended in all hysteroscopies showing unevenly shaped and thick endometrial mucosa or an anatomically distorted uterine cavity, and when endouterine visualization is less than optimal.