Ultrasonic typing and diagnostic value of intravenous leiomyomatosis: a single-center retrospective study.

OBJECTIVE: To propose an ultrasound-based classification system for intravenous leiomyomatosis (IVL) and to describe the sonographic features of each type using standardized terminology, with the aim of facilitating disease recognition and preoperative decision making. METHODS: A retrospective analysis was performed on 88 pathologically confirmed IVL cases. Ultrasound findings were compared with intraoperative observations, frozen section pathology, and postoperative pathology. Three experienced sonographers independently described the imaging features using standardized terms. RESULTS: Based on ultrasound findings, IVL was classified into four types: Type I (uterine type, 52/88, 59.1%), Type II (parauterine type, 22/88, 25.0%), Type III (combined uterine and parauterine type, 12/88, 13.6%), and Type IV (extrapelvic type, extending to heart/lungs, 2/88, 2.3%). The preoperative diagnostic accuracy was only 14.8% (14/88), with a misdiagnosis rate of 84.1% (74/88). All 52 Type I lesions were misdiagnosed, most commonly as uterine fibroids (47/74). Characteristic ultrasound signs included slit-like anechoic areas within the lesion (especially when internal blood flow was visible) and vermiform or articulated masses along the uterine/parauterine veins. CONCLUSION: Ultrasound may play a useful role in the early identification, preoperative typing, and extent assessment of IVL. The proposed four-type classification and characteristic signs provide valuable imaging references for surgical planning and multidisciplinary care. When suspicious signs are detected, extended ultrasound to the iliac veins, inferior vena cava, and heart, along with CT/MRI, may be considered.