[1099] Correlation of K-Ras Mutation with Histological Subtypes of Endometrial Mucinous Lesions: Implications for Biological Progression and Molecular Diagnosis

Ahmed Alomari, Rita Abi-Raad, Natalia Buza, Pei Hui. Yale University School of Medicine, New Haven, CT

Background: Mucinous epithelial changes are frequently encountered in endometrial biopsies. Traditionally they have been classified into three morphologic categories (A, B and C) based on architectural complexity and cytological atypia to help predicting the risk of subsequent endometrial adenocarcinoma (EAC). K-ras mutations have been recently reported in atypical mucinous endometrial lesions and mucinous EAC. The aim of our study was to assess the prevalence and diagnostic and prognostic utility of K-ras mutation in the different morphological classes of mucinous endometrial changes.
Design: Forty endometrial biopsies with mucinous change were retrieved from our departmental archives. All available H&E slides were reviewed and the cases were categorized into simple mucinous change without cytological atypia (type A), complex mucinous epithelium or simple mucinous changes with cytological atypia (type B), markedly complex mucinous changes with cytological atypia (type C) or mucinous EAC. K-ras mutation analysis was performed by single strand conformation polymorphism. Clinical data and follow up were recorded.
Results: Thirty-eight cases with informative K-ras mutation status were included in the final analysis, including 2 type A lesions, 18 type B lesions and 11 type C lesions. Follow-up was available for 32 patients. All type A mucinous lesions were negative for K-ras mutation. K-ras mutation was present in 61.1% of type B mucinous lesions, in 45.5% of type C mucinous lesions, and in 85.7% of EAC. Additional details and follow-up information is presented in table 1.

Table 1. Results
Type of mucinous changeNumber of cases (total n=38)Number of K-ras positive casesNumber of cases with follow up (total n=32)Follow up diagnosis
   K-ras positiveK-ras negativeK-ras positive n (%)K-ras negative n (%)
A2001NA1 (100%) IE
B1811 (61.1%)955 (55.6%) CAH, 0 (0%) EAC0 (0%) CAH, 2 (40%) EAC
C115 (45.5%)463 (75%) CAH, 1 (25%) EAC3 (50%) CAH, 0 (0%) EAC
EAC76 (85.7%)616 (100%) EAC1 (100%) EAC
CAH: Complex Atypical Hyperplasia, EAC: endometrial adenocarcinoma, IE: Inactive endometrium, NA: not applicable

Conclusions: Corroborating the existing data, the current study confirms high incidence of K-ras mutation in atypical mucinous epithelial lesions (type B and C) and mucinous carcinoma of the endometrium. Therefore, K-ras mutation may be a clinically useful molecular marker of early stage malignant transformation of mucinous lesions of the endometrium.
Category: Gynecologic & Obstetrics

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 169, Monday Morning


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