Ultrasound features using MUSA terms and definitions in uterine sarcoma and leiomyoma: retrospective cohort study

ABSTRACT Objective A timely and correct preoperative diagnosis of a uterine sarcoma will increase patients’ survival. The primary aim of our study was to describe the ultrasound features in uterine sarcomas compared to uterine leiomyomas based on MUSA (Morphological Uterus Sonographic Assessment) terms and definitions. The secondary aim was to assess the interobserver agreement of the MUSA ultrasound features. Methods This retrospective cohort study assessed uterine sarcomas from 1997 until 2019 and uterine leiomyomas from 2016 until 2019 treated in a single tertiary center. Patients’ demographics, presenting symptoms and outcome were extracted from the patients’ files. The ultrasound images were re‐evaluated independently by two sonologists using the MUSA terms and definitions. Descriptive statistics were calculated and interobserver agreement was assessed with Cohen's Kappa (with squared weights) or intraclass correlation coefficient depending on the type of variable. Results Hundred and seven patients were included, of whom 16 had a uterine sarcoma and 91 a uterine leiomyoma. Abnormal uterine bleeding was the most frequent presenting symptom (69/107, 65%). Compared to leiomyoma cases, uterine sarcoma patients were older (mean age of 65 years (IQR 60‐70 years) versus (vs.) 48 years (IQR 43‐52 years)) and mostly postmenopausal (13/16 (81%) vs. 15/91 (16%)). In the uterine sarcoma cohort, leiomyosarcoma was the most frequent histological type (6/16 (38%) followed by adenosarcoma (4/16 (25%). On ultrasound evaluation, according to observer 1 and 2, the tumor border was irregular in most sarcomas (in 11/16 (69%) and 13/16 (81%), respectively), whereas leiomyomas were most frequently regular (in 65/91 (71%) and 82/91 (90%), respectively). The observers classified the lesion echogenicity as non‐uniform, in 68/91 (75%) and 51/91 (56%) of leiomyomas and 15/16 (94%) of uterine sarcoma. More than 60% of the uterine sarcomas showed acoustic shadows (in 11/16 (69%) and 10/16 (62%) respectively) whereas calcifications were reported in a small minority of them (in 0/16 (0%) and 2/16 (13%) respectively). In uterine sarcomas, the intralesional vascularity was reported as moderate to abundant in 13/16 (81%) and 15/16 (94%) respectively while circumferential vascularity was scored as high in 6/16 (38%) by both observers. The interobserver agreement for presence of cystic areas, calcifications, acoustic shadow and central necrosis, color score (overall, intralesional and circumferential), and maximal diameter of the lesion, was moderate. The agreement for lesion tumor border and echogenicity was fair. Conclusions A postmenopausal patient, presenting with abnormal uterine bleeding and a new or growing mesenchymal mass with irregular tumor borders at ultrasonography, moderate to abundant intralesional vascularity, presence of cystic areas and absence of calcifications, carries a higher risk of having a uterine sarcoma. The interobserver agreement for most MUSA terms and definitions is moderate. Future studies should validate the above clinical and ultrasound findings in a prospective multicenter collection of uterine mesenchymal tumors. This article is protected by copyright. All rights reserved.