Ultrasound Characteristics of Twisted Pedunculated Subserosal Uterine Leiomyomas: A Case Report and a Systematic Review of the Literature

Torsion of pedunculated subserosal uterine leiomyomas (TPSUL) is a rare but potentially severe condition that may require emergency surgery. This article aims to summarize the existing literature by presenting a systematic review and an illustrative case report. A total of 38 articles describing 42 cases of TPSUL were analyzed to identify recurring ultrasound features that may aid in preoperative diagnosis. The most frequently reported findings included a mean maximum diameter of approximately 10 cm, increased size compared to prior scans (100%), heterogeneous echotexture (81%), regular borders (90%), and posterior or trans-lesional acoustic shadows (94%). Additional common features were the presence of free pelvic fluid (57%), cystic areas with irregular margins and hypo-anechoic content (55%), and absent (68%) or reduced (32%) vascularization of the lesion. A vascular pedicle was identified in 28% of cases, with signs of torsion in 12.5% and interruption of vascular flow at the pedicle base in 25%. The ultrasound features observed in our case, involving a 29-year-old pregnant patient at 21 weeks' gestation, were consistent with those described in the literature. These findings support the role of ultrasound as a useful tool for the preoperative identification of TPSUL and lay the foundation for future diagnostic standardization.