OC21.06: Central necrosis in uterine sarcomas

Several attempts have been made to develop a more objective, ultrasound-based definition for central necrosis to discriminate between uterine sarcomas and leiomyomas. The aim of this study was to provide a new standardised definition for the sonographic appearance of central necrosis, based on the results of a retrospective final analysis and the last updated available evidence. A blinded analysis of 15 uterine sarcomas and 31 leiomyoma ultrasound (US) images was conducted by two experienced US examiners. Central necrosis was evaluated according to the following definition: irregular, mostly hyperechogenic, avascular area with or without a central anechoic cystic area within a moderately to highly vascularised solid lesion. US examiners were blinded to any clinical or histopathological patient information. A pathologist reviewed the histopathology on the presence of necrosis. According to the provided definition, central necrosis was observed in 79% of uterine sarcoma and 17% of leiomyoma cases. In 60% (9/15) of uterine sarcomas and 0% of the leiomyomas, necrosis was present on histopathology. In 5 of the 9 cases (55.5%) in which necrosis was reported on the histopathological examination, the two examiners concurred in identifying cystic and hyperechoic area at the ultrasound. However, when focusing only on cases where the initial pathologist described the presence of necrosis as “markedly evident”, “extensive” or reported the presence of “multiple foci of necrosis”, the consensus between the two US examiners in detecting these ultrasound features reached the 70% (5/7). Our study supports the usefulness of ultrasound in assessment of central necrosis to discriminate between leiomyomas and uterine sarcomas. Additional studies are required to investigate the sonographic characteristics of central necrosis in the identification of uterine sarcomas, alongside assessing both interobserver and intraobserver variability, using a larger and more representative sample size.