[1158] Endometrial Biopsy Interpretation Using WHO 2004 and EIN Criteria: An Analysis of 77 Cases with Emphasis on Conservative Management

Kari K Hooper, Pamela J Stone, Charles M Quick. UAMS, Little Rock, AR

Background: Endometrial Intraepithelial Neoplasia (EIN) is a recently described, alternative staging system for endometrial hyperplasia that has been cited as a discerning and reproducible means of predicting the development of endometrial adenocarcinoma. In this study we compare the WHO and EIN classifications using lesions previously classified as hyperplasia, and correlated them with clinical outcome in a patient population treated with hormone therapy.
Design: Seventy-seven WHO classified hyperplasias (all types) from 2004 to 2011 were analyzed. The reviewers were unaware of the initial diagnosis. EIN criteria were applied (gland to stroma ratio at least 55%, cytologic alteration, size > 1mm, exclusion of mimics/cancer). Reclassified cases were compared to the WHO classification, and correlated with clinical treatment and pathologic follow up.
Results: 77 cases (70 with follow up) were available for review; 38 (49%) met criteria for EIN. These 38 were originally classified as complex atypical hyperplasia (CAH) (14, 37%), complex hyperplasia (CH) (23, 60%) and simple atypical hyperplasia (1, 3%). The 39 cases that did not meet EIN criteria consisted of polyps (10, 26%), subdiagnostic atypical or crowded glands (13, 33%), benign hyperplasia (3, 8%) and benign endometrium (13, 33%). Of the 70 patients with available follow-up, 33 (47%) were treated with hormones. Of these, 15 patients (45%) had negative follow up biopsies. 2 patients (6%) went to hysterectomy and were diagnosed with carcinoma (5 & 11 months), and 1 (4%) had residual EIN on follow up. 15 patients (45%) had no biopsy follow up (12 had no evidence of disease clinically, 2 had persistent bleeding but were not re-biopsied, and 1 was lost to follow up). Clinical follow up ranged from 1-83 months with a mean of 16 months. None of the patients who did not meet EIN criteria developed endometrial carcinoma, and all patients who developed endometrial carcinoma were reclassified as EIN during the review.
Conclusions: EIN criteria is sensitive (100%), has an excellent negative predictive value (100%) in that none of the cases that did not meet EIN criteria developed carcinoma, and provides an objective approach to endometrial biopsy interpretation. Medical management of EIN is a viable alternative to surgical therapy in the proper clinical setting, with only 6% progressing to carcinoma over our follow up period. Due to the high negative predictive value of the EIN criteria, patients without EIN may be conservatively managed.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 129, Tuesday Afternoon


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