Clinical and ultrasound characteristics of uterine perivascular epithelioid cell tumors.

PURPOSE: To describe the ultrasound characteristics of uterine perivascular epithelioid cell tumors (PEComas). MATERIALS AND METHODS: This retrospective multicenter case series included patients from two Italian academic centers specializing in oncological care. All women with histologically confirmed uterine PEComas between January 2013 and December 2024 and available clinical and ultrasound data were included. Ultrasound images were reviewed by three expert sonographers using Morphological Uterus Sonographic Assessment (MUSA) terminology. RESULTS: Thirteen patients were identified, including 8 malignant and 5 benign PEComas. The median age was 54 years (IQR 46-65). Six patients (46%) were asymptomatic, five (38%) presented with abnormal uterine bleeding, one (8%) with pelvic pain, and one (8%) with abdominal bloating. Tumors originated from the cervix (38%), uterine corpus (46%), and isthmus (15%). On transvaginal ultrasound, most PEComas appeared as solitary, round, solid masses with regular margins (62%) and inhomogeneous echogenicity (69%), with a median diameter of 42 mm (IQR 23-66). Irregular cystic areas were observed in six cases (46%), while shadowing and hyperechoic islands were absent. Power Doppler assessment revealed moderate to rich vascularization (color score 3-4) in 9 cases (69%). Malignancy was suspected on initial ultrasound in only 4 cases (31%). CONCLUSION: Uterine PEComas commonly present as solitary, solid, round masses with regular margins, inhomogeneous echogenicity, and marked vascularization. Typical features such as shadowing or hyperechoic islands are absent. Despite these characteristics, malignancy is often underrecognized on initial ultrasound.