Presentation
Long history of vague lower abdominal and pelvic pain with associated fullness and a painless palpable lump.
Patient Data
A large soft tissue pelvic mass is identified on ultrasound, demonstrating a heterogeneous echotexture, closely adherent to the adjacent uterine fundus, with internal and peripheral vascularity on color Doppler.
There is a large lobulated midline pelvic soft-tissue mass, compressing the dome of the urinary bladder. It appears isointense to the surrounding soft-tissues on T1-weighted images, iso-to-hypointense on T2 and demonstrates a relatively heterogeneous pattern of enhancement on the contrasted study. This mass is in very close proximity to the anterior surface of the uterine fundus, connected to the uterus by a short pedicle, with multiple tiny tortuous feeding vessels extending from the uterine body to its center.
Findings are consistent with a large pedunculated subserosal uterine leiomyoma.
Two smaller intramural and submucosal uterine fibroids are evident.
A moderate amount of pelvic free fluid is present.
Bridging vessel sign
Annotated ultrasound:
bridging vessel: yellow arrow
pedunculated subserosal fibroid: green asterisk
uterine fundus: yellow asterisk
Annotated MRI:
Arrows clearly point to multiple tortuous vascular structures with luminal signal voids connecting the uterus to the adjacent pelvic mass (bridging vessel sign).
Case Discussion
This case nicely demonstrates the "bridging vessel" sign, which is a very useful sign in determining the uterine origin of a pelvic mass, with high specificity and sensitivity.
It was first described on Doppler studies, but can also be appreciated on other cross-sectional imaging modalities.
Multiple tortuous vessels can be seen connecting the uterus to an adjacent pelvic mass, usually a pedunculated subserosal fibroid. This sign will help to differentiate a mass of uterine origin from other pelvic masses originating from the adnexa or bowel. It is best seen in fibroids that are larger than 3 cm.
In this case, the lesion described was initially thought to arise from the adjacent sigmoid colon, until these feeding vessels were identified.