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Adenomyosis Imaging Spectrum
Adenomyosis is a benign condition characterized by heterotopic endometrial tissue within the myometrium, affecting women of reproductive age. It presents clinically with hypermenorrhea, dysmenorrhea, and chronic pelvic pain, and is frequently associated with infertility and adverse assisted reproductive outcomes.
Key Images
Figure 1. Endovaginal US and MRI features of typical adenomyosis in different patients who are in the menacme.
- (A) Transverse US image shows a myometrial cyst (white arrow) and a hyperechoic island (black arrow). Notice the fan-shaped shadowing.
- (B) Longitudinal US image shows echogenic lines (arrows).
- (C) Axial T2-weighted MR image shows a focal thickening of the JZ (white arrows), with embedded high-signal-intensity foci corresponding to ectopic glands (black arrow).
- (D) Sagittal T2-weighted MR image shows a diffusely enlarged uterus with thickening of the JZ (white arrows) and low signal intensity of the myometrium, with innumerable hyperintense foci (black arrows) scattered in the lesion.
Figure 2. Physiologic transient myometrial contractions simulating adenomyosis in a 26-year-old woman.
- Sagittal T2-weighted MR images acquired a few minutes apart show a focal area of low signal intensity perpendicular to the JZ on the posterior uterine wall (arrows in A) that vanishes after a few minutes (B).
Figure 3. Deeply infiltrative endometriosis in two different women of reproductive age, both with severe dysmenorrhea.
- (A) Longitudinal US image shows a hypoechoic plaque lesion in the posterior uterine serosa, with small cystic areas infiltrating the myometrium (*) and causing uterine retractile retroflexion (dashed line).
- (B) Axial T2-weighted MR image shows a hypointense lesion in the posterior surface of the uterus, with multiple small hyperintense foci corresponding to endometrial glands (white arrows). The JZ appears normal (black arrows).
- (C) Laparoscopic view shows obliteration of the pouch of Douglas (*) with the rectum
- (R) tethered to the lesion (arrows) in the posterior aspect of the uterus (U). (Courtesy of Ricardo M. A. Pereira, MD.)
Figure 4. Adenomyoma in a 34-yearold woman with menorrhagia.
- Sagittal T2-weighted MR image shows a hypointense intramyometrial nodule in the posterior uterine wall, with partially defined margins, minimal mass effect, and small internal hyperintense foci (arrows).
Figure 5. Subserosal adenomyoma in a 36-year-old woman with heavy menstrual cramps since adolescence that worsened in the last year.
- (A) Sagittal T2-weighted MR image shows a subserosal mass (arrows) in the posterior uterine wall, with heterogeneous signal intensity.
- (B) Sagittal T1-weighted MR image with fat saturation shows the mass (arrows) with areas of high signal intensity, indicating hemorrhagic content.
- (C) Photograph of gross specimen shows that it contains a large amount of chocolate-colored fluid.
Figure 6. Submucosal cystic adenomyoma in a 45-year-old woman with infertility.
- Sagittal T2-weighted MR image show a round heterogeneous cystic lesion (arrow) distorting the uterine cavity.
Figure 7. Cystic adenomyoma in a 42-year-old woman with Herlyn-Werner-Wunderlich syndrome.
- (A) Coronal T2-weighted MR image of the uterus shows a subserosal cystic lesion in the left hemiuterus (arrow).
- (B) Laparoscopic view shows the lesion (circle). (Courtesy of Ricardo M. A. Pereira, MD.)
Figure 8. Tips for the differential diagnosis of cystic adenomyoma, leiomyoma with cystic degeneration, ACUM, and unicornuate uterus with a functional uterine remnant.
- T2WI = T2-weighted MRI.
Figure 10. Presumed adnexal lesion in a 42-year-old woman with a postsurgical diagnosis of an extrauterine adenomyoma.
- (A) Axial T2-weighted MR image shows a lobulated mass (arrows) in the right pelvic paramedian region, containing cystic areas with high signal intensity interspersed with a hypointense fibrous stroma.
- (B) Axial T1-weighted MR image with fat suppression shows small hemorrhagic cystic foci in the lesion (arrows).
- (C) Photograph of the surgical specimen shows whorled, white, firm areas.
Figure 9. ACUM in a 14-year-old nulliparous adolescent girl with intense dysmenorrhea since menarche.
- (A) Axial T2-weighted MR image shows a cystic cavity lined with endometrium and surrounded by a hypointense halo in the left uterine body (arrow).
- (B) Axial T1-weighted MR image with fat saturation shows prominent high signal intensity in the central cavity, corresponding to hemorrhagic content (arrow).
- (C) Laparoscopic surgical view shows the mass on the left side of the uterus, bulging the organ (dashed circle).
- (D) Laparoscopic surgical view shows a section of the mass with chocolate-colored fluid spilling out.
Figure 11. Atypical polypoid adenoma in a 50-year-old woman.
- (A) Sagittal T2-weighted MR image shows an enlarged uterus with multiple hypointense masses representing leiomyomas (*) and a polypoid lesion anchored in the lower uterine segment, protruding into the vagina (arrows).
- (B) Sagittal T1-weighted MR image with fat suppression shows a small hemorrhagic focus in the lesion (arrow).
- (C) Sagittal postcontrast MR image shows irregular areas of enhancement.
- (D) Diffusion- weighted MR image shows peripheral restriction (arrows).
Figure 13. Polypoid adenomyoma in a 35-year-old woman.
- (A) Longitudinal endovaginal US image shows a polypoid lesion in the endometrial cavity (arrows).
- (B) Axial T2-weighted MR image shows that the lesion is anchored in the right uterine body wall with mild myometrial infiltration (white arrow) and contains a predominantly cystic component in its central portion. Uterine adenomyosis is also observed (black arrows).
- (C) Hysteroscopic view shows the lobulated surface of the polyp.
in a 33-year-old woman shows a hypointense intramyometrial mass in the left uterine wall with partially defined margins, minimal mass effect, and small internal hyperintense foci, which are findings characteristic of an adenomyoma (arrows).
- (B) Axial T2-weighted MR image during the third trimester of pregnancy when the patient was 36 years old shows a heterogeneously thickened left myometrium with scattered cystic areas (arrows). A normal placenta (black *) and an additional finding of a leiomyoma (white *) are also visible.
Figure 17. Endometrioid adenocarcinoma in a 52-year-old woman who was undergoing imaging follow-up for uterine adenomyosis. (A, B) Sagittal
- (A) and axial
- (B) T2-weighted MR images reveal a diffusely enlarged uterus with adenomyosis (*) and a lobulated mass of intermediate to high signal intensity located in the posterior uterine wall (arrows).
- (C) Laparoscopic view shows the mass.
- (D) Photomicrograph shows marked nuclear pleomorphism (arrow).
Figure 18. Adenomyosis in a 46-year-old woman with confirmed low-grade endometrial stromal sarcoma. (A, B) Axial
- (A) and sagittal
- (B) T2-weighted MR images show a large myometrial cystic mass abutting the uterine cavity (arrows). (C, D) Axial
- (C) and sagittal
- (D) T2-weighted MR images acquired 3 years later show substantial growth of the lesion (arrows), which exhibits prominent high signal intensity and a peripheral hypointense component (*) corresponding to solid areas or clots . The patient did not receive intravenous contrast material due to a history of allergy.
- (E) Photograph of the surgical specimen shows the mass (*).
Look For First
- Junctional zone (JZ) thickening or irregularity on sagittal T2-weighted MRI or endovaginal ultrasound
- Myometrial cysts appearing as hyperintense foci on T2-weighted MRI or anechoic foci on endovaginal ultrasound
- Subendometrial hyperintense linear streaks on T2-weighted MRI or echogenic lines and buds on endovaginal ultrasound
- Ill-defined areas of low signal intensity on T2-weighted MRI or hypoechoic regions on ultrasound indicating smooth muscle hyperplasia
Key Image Findings
- On T2-weighted MRI, adenomyosis demonstrates subendometrial hyperintense linear streaks (representing ectopic endometrial glands) and myometrial hyperintense cysts (from cyclic proliferation and hormone secretion by heterotopic glands), considered the most reliable sign of adenomyosis.
- T2-weighted MRI shows ill-defined areas of low signal intensity representing smooth muscle hyperplasia and hypertrophy, often with an indistinct lower boundary between the endometrium and inner myometrium.
- Myometrial cysts frequently contain hemorrhagic content, appearing as high signal intensity on T1-weighted MRI, allowing distinction from simple cysts and supporting adenomyotic origin.
- On endovaginal ultrasound, adenomyosis presents as hyperechogenic islands, echogenic subendometrial lines and buds, myometrial cysts (anechoic foci), and fan-shaped shadowing.
- JZ thickness greater than 12 mm on MRI or indirect features including globular uterus, asymmetric myometrial wall thickening, translesional vascularity, and JZ interruption/irregularity support the diagnosis.
- Focal adenomyosis shows localized signs with greater than 25% of lesion circumference surrounded by normal myometrium and may present with JZ bulging; diffuse adenomyosis affects the entire myometrium without clear circumscription.
- MRI is superior to endovaginal ultrasound for distinguishing adenomyosis from transient uterine contractions through assessment in multiple orthogonal planes at different time points.
- Gadolinium-based contrast material aids in characterizing atypical features and distinguishing adenomyosis from leiomyomas and endometrial polyps, though not required for typical adenomyosis diagnosis.
Differential Diagnosis
- Uterine contractions—can mimic adenomyosis on single images but resolve on images obtained at different time points; MRI evaluation in multiple planes is essential to exclude this mimic.
- Leiomyomas—typically have well-defined margins, low T2 signal intensity, and may show degenerative changes, unlike adenomyosis which is ill-defined with mixed signal; gadolinium enhancement helps distinguish them.
- Endometrial polyps—appear as focal endometrial thickening without junctional zone disruption and without myometrial involvement, distinguishable by their superficial location and better-defined margin.
- Deep infiltrating endometriosis with myometrial infiltration—can cause JZ thickening and irregular margins but typically has clear endometrial origin and may have associated peritoneal endometriosis elsewhere.
- Accessory cavitated uterine masses (ACUM)—appear as cystic lesions within myometrium but lack internal epithelial lining continuity with endometrial cavity and have different clinical significance.
- Malignant transformation (sarcoma)—shows suspicious myometrial location, rapid growth, and severe adenomyotic changes; diagnosis often requires comparison with prior imaging and pathologic confirmation of adenomyotic tissue origin.
Discussion
Adenomyosis results from either invagination of basal endometrium into myometrium (leading to indistinct lower JZ boundary) or differentiation of embryonic müllerian remnants, accounting for adenomas distant from the JZ.
Risk factors include parity, miscarriages, and uterine surgical procedures (dilation and curettage, induced abortion), though the relationship with prior cesarean delivery remains debated.
Clinical correlation reveals that approximately two-thirds of patients develop symptoms (hypermenorrhea, dysmenorrhea, chronic pelvic pain) that may not correlate with disease severity, complicating clinical diagnosis.
Diffuse adenomyosis has more pronounced negative effects on assisted reproductive treatment outcomes than focal adenomyosis, emphasizing the need for standardized classification to guide management.
While histologic examination after hysterectomy remains the gold standard, endovaginal ultrasound (72% sensitivity, 81% specificity) and MRI (77% sensitivity, 89% specificity) are emerging as viable noninvasive diagnostic alternatives.
The MUSA consensus (since 2019) has established standardized terminology and classification for adenomyosis, with direct features (myometrial cysts, hyperechogenic islands, echogenic lines) being more specific than indirect features.
Reporting Pearls
When reporting adenomyosis, clearly state whether the pattern is focal or diffuse, the estimated extent of myometrial involvement (mild <25%, moderate 25-50%, severe >50%), specify the presence and location of myometrial cysts and JZ abnormalities, and note the presence of any hemorrhagic content (T1 hyperintensity) to substantiate diagnosis—this facilitates clinical correlation and guides fertility counseling.
Pitfalls
- Confusing transient uterine contractions with adenomyosis; always evaluate the JZ in multiple orthogonal planes at different time points, or use delayed imaging sequences on MRI, to resolve ambiguity between normal contractility and pathologic JZ thickening.
- Over-relying on JZ thickness alone (>12 mm) as a diagnostic criterion, which has been challenged in premenopausal women; instead, prioritize JZ irregularity and myometrial cysts as more specific markers.
- Missing adenomyosis in the cornual regions on two-dimensional ultrasound; three-dimensional ultrasound should be used when feasible to better visualize subtle JZ changes in these areas.
- Failing to administer gadolinium contrast in atypical cases; contrast-enhanced MRI is essential for characterizing unusual adenomyosis features and excluding other benign and malignant conditions such as leiomyomas and sarcoma.