Sonographic and histopathologic characteristics of MMR-deficient endometrial cancer.

Abstract

e17111 Background: Mismatch repair (MMR) deficiency has emerged as a key biomarker in endometrial cancer with roles in prognosis and guiding therapy. However, the differences of sonographic features between MMR-deficient and MMR-proficient endometrial cancers at initial presentation have not been established. Methods: Transvaginal ultrasound studies of 103 endometrial cancers (60 MMR-deficient, 43 MMR-proficient) at initial presentation were retrospectively analyzed by two experienced radiologists. Histopathologic findings and sonographic features of endometrial morphology recorded according to IETA terminology were compared using Likelihood Ratio Chi-Square and Mann–Whitney U tests. Results: The MMR-deficient group comprised of 90% and the MMR-proficient group of 100% endometrioid subtypes. The following sonographic features were statistically different between MMR-deficient (age 45-95) and MMR-proficient (age 45-83) groups: uniform endometrial echogenicity/pattern, non-uniform endometrial echogenicity/pattern, endometrial midline morphology, presence of a bright edge, and endomyometrial junction morphology. Ultrasound findings of endometrial thickness, synechiae, intracavitary fluid, color Doppler score, and vascular pattern were not significantly different. Statistically significant differences in pathology features included FIGO grade, myometrial invasion, and lymphovascular invasion, while FIGO stage showed no difference. Conclusions: MMR-deficient endometrial cancer is characterized by several statistically different ultrasound and histopathologic features on initial presentation compared to MMR-proficient endometrial cancer.[Table: see text]