OBJECTIVE: To examine whether the co-occurrence of endometriosis affects the sonographic features of adenomyosis based on the revised Morphological Uterus Sonographic Assessment (MUSA) criteria. METHODS: This prospective cohort study utilized data from a tertiary referral center collected between 2010 and 2022. Non-pregnant women aged 20-53 years who presented with symptoms potentially related to adenomyosis and underwent pelvic ultrasound scans were included. Diagnoses were based on the revised MUSA criteria, which distinguish between direct features (endometrial cysts, hyperechogenic islands, echogenic sub-endometrial lines, and buds) and indirect features (globular shape of the uterus, asymmetrical uterine wall thickening, irregular junctional zone, fan-shaped shadowing, translesional vascularity, and interrupted junctional zone). Patients were categorized into 2 groups: 1) concurrent adenomyosis and endometriosis and 2) isolated adenomyosis. Demographic and clinical characteristics were retrospectively collected. RESULTS: Ninety-four patients were diagnosed with adenomyosis. Of these, 24 (27%) had concurrent endometriosis, while 70 had isolated adenomyosis. The most frequent sonographic features were globular uterine configuration (52%), myometrial cysts (44%), and asymmetrical myometrial thickening (33%). The isolated adenomyosis group had a higher proportion of direct features (29%) and both direct and indirect features (33%) compared to the concurrent group, which predominantly exhibited indirect features (71%) (P <
.05). Direct features of myometrial cysts were significantly more frequent in the isolated adenomyosis group (51%) compared to the concurrent group (21%, P = .01). CONCLUSIONS: Utilizing the revised MUSA criteria revealed significant differences in the sonographic features of adenomyosis in symptomatic patients with concurrent endometriosis compared to isolated adenomyosis. This highlights the necessity for standardized diagnostic methods and enhances understanding of the complex relationship between adenomyosis and endometriosis, underscoring the importance of accurate diagnosis in clinical practice.