Endometrial Intraepithelial Neoplasia And Its Correlation With WHO Classified Endometrial Hyperplasia

摘要

Introduction: Endometrial hyperplasia produces a continuum of lesions that may be precursor to endometrial carcinoma of endometrioid histology. The World Health Organization (WHO) classification is currently the most commonly accepted system of classifying endometrial hyperplasias, the problems with which have prompted the development of an alternative system based on Endometrial Intraepithelial Neoplasia (EIN).Materials and Methods: We undertook the study using revised EIN criteria to differentiate EIN lesions from lookalikes. EIN diagnostic criteria’s, such as gland area>stromal area, cytologic change in focus of altered architecture, lesion size>1 mm and exclusion of cancer and mimics were applied on two hundred endometrial biopsies that were initially classified as hyperplasia using WHO classification system.Results: Out of total two hundred cases, 41.5% were diagnosed as simple typical hyperplasia, 19% cases as complex typical hyperplasia, 9.5% cases as simple atypical hyperplasia and 30% cases as complex atypical hyperplasia respectively. Out of these WHO classified hyperplasias, 39% were re-classified as EIN and 61% as non-EIN lesions. Majority of WHO classified atypical hyperplasias were reclassified as EIN. Conclusion: EIN criterias can easily be applied to routine haematoxylin and eosin stained sections and is more reproducible than WHO system of classification. Few of the lesions diagnosed as simple hyperplasia without atypia correspond to EIN and have a worse prognosis. EIN successfully segregates patients into high and low cancer risk groups. Introduction Due to inadequately supported reproductive pathologic criteria’s in existing World Health Organization (WHO) classification of endometrial hyperplasia, the diagnosis of precancerous lesions of the endometrium remains unstandardized1. There are many shortcomings in the WHO endometrial hyperplasia classification system that subclassifies hyperplasia by cytology as atypical / non atypical and architecture as complex / non complex.2,3 Overall reproducibility of atypical hyperplasia diagnosis is poor, because of nonspecific reporting patterns and intra/inter-observer variation which leads to confusion among clinicians and pathologists. The Endometrial Collaborative Group, an international group of 19 pathologists has recently attempted to clarify the concept of endometrial neoplasia and proposed two categories of endometrial lesions, endometrial hyperplasia and endometrial neoplasia, the latter divided into intra-epithelial and invasive neoplasia. True endometrial hyperplasia rarely progresses to neoplasia while lesions formerly designated as “atypical hyperplasia” are presently reclassified as Endometrial Intraepithelial Neoplasia (EIN), which carries a significant risk of progression into invasive carcinoma4,5. According to Endometrial Collaborative Group, there are many advantages to diagnose premalignant endometrial disease as EIN such as 1) Pre-cancers should be placed in a single diagnostic category 2) Pre-cancers are monoclonal and thus neoplastic and parallelism with other pre-cancerous nomenclature systems elsewhere in the female genital tract is required 3) Endometria which do not meet diagnostic criteria for EIN can be diagnosed as “Endometrial Hyperplasia” to distinguish them from EIN lesions. Long term prospective multicenter studies have shown that the EIN system is prognostically superior then other commonly used systems9. Based on these considerations, the present study was designed to review Endometrial Intraepithelial Neoplasia (EIN) and to correlate it with WHO classification of endometrial hyperplasia. Materials And Methods Two hundred patients who were not on therapeutic hormones and who presented with abnormal vaginal bleeding were included in this study. The histopathological material consisted of dilatation and curettage, endometrial biopsy and hysterectomy specimen. The material was fixed in 10% formalin and processed in graded alcohol and xyl