Ultrasound Features of Uterine Perivascular Epithelioid Cell Tumor (PEComa): A Systematic Review.

Uterine perivascular epithelioid cell tumor (PEComa) is a rare mesenchymal neoplasm whose sonographic profile has not been systematically characterized. We describe an index case of malignant uterine PEComa and present a PRISMA 2020-compliant systematic review (PubMed, Scopus, Cochrane Library; search 1 March 2026) of studies reporting original ultrasound data of histologically confirmed uterine PEComa. Sonographic features were coded with MUSA/IETA terminology; Clopper-Pearson 95% confidence intervals (CI) were calculated for key proportions, and malignancy subgroups were summarized descriptively. Thirty-one cases were pooled (30 from 18 studies plus our index case; median age 41 years). The profile comprised absent acoustic shadowing in all documented cases (10/10; 95% CI 69.2-100%), moderate-to-abundant vascularisation (Color Score 3-4, 91.7%), variable echogenicity (heterogeneous 56.0%) and predominantly regular margins (69.6%). Preoperative misdiagnosis occurred in 100% of cases, most often as leiomyoma (41.4%). In cases with known malignancy status (n = 17), irregular margins and cystic areas appeared more often in malignant lesions, but subgroups were too small for testing. Only 4/18 studies applied standardized terminology. Uterine PEComa shows a recurrent pattern of absent shadowing, high vascularisation and solid consistency with regular margins that may aid differential diagnosis; systematic adoption of MUSA/IETA terminology in future reports is strongly advocated.