Ultrasound of Uterine Adenomyosis

In this radiology lecture, we review the ultrasound appearance of adenomyosis through three unique cases, including an MRI example.

Key teaching points include:

Adenomyosis results from ectopic endometrial tissue in myometrium. Leads to dysfunctional smooth muscle hyperplasia/hypertrophy surrounding ectopic glands.
Cause unknown.
Common, usually multiparous women of reproductive age.
Additional risk factors: Early menarche, short menstrual cycles, high BMI = High estrogen exposure.
Rarely seen in postmenopausal patients, unless treated with tamoxifen for breast cancer.
Often asymptomatic, but can present with menorrhagia, dysmenorrhea, dyspareunia, and chronic pelvic pain.
For diagnosing adenomyosis, transvaginal US much more sensitive and specific (89%) than transabdominal imaging.
Most specific US findings: Linear echogenic striations/nodules radiating from endometrium into inner myometrium. Tiny myometrial and subendometrial cysts = Fluid-filled glands.
Additional US findings: Enlarged, globular uterus with diffuse myometrial bulkiness, myometrial heterogeneity, irregular endometrial-myometrial interface, hyperechoic islands, and pencil-thin “venetian blind” or “rain shower” shadowing. Cine clips extremely helpful.
Adenomyosis can cause asymmetric myometrial thickening.
Focal adenomyosis (adenomyoma) has ill-defined margins compared to fibroids, typically elliptical as opposed to rounded in shape.
May see abnormal vascular flow: Increased vascularity with tortuous vessels penetrating myometrium. Helps differentiate adenomyosis from fibroids, which tend to displace vessels and show circumferential flow.
On US, thickened junctional zone may manifest as a hypoechoic halo surrounding echogenic endometrium.
MRI “traditionally” the modality of choice to diagnose adenomyosis, and junctional zone thickened to 12 mm or greater highly specific. May contain punctate T2 hyperintense cystic foci/T1 hyperintense hemorrhage.
However, modern TV US shows comparable accuracy to MRI with no statistical significance between sensitivities and specificities: “Transvaginal US should be considered the primary imaging modality for the diagnosis of adenomyosis.”*
Treatment: Pain management, tranexamic acid, OCPs, GnRH agonists.
If severe, not relieved medically, and no desire for fertility: Hysterectomy.