Congenital Uterine Anomalies

Congenital Uterine Anomalies

Embryogenesis Overview

Embryogeneisis OverviewMullerian Duct Anomalies (MDAs)

  • 1-5% of the general population and 13-25% of patients with infertility or recurrent pregnancy loss (1)
  • Affecting fallopian tubes, uterus, cervix, and proximal 2/3 of the vagina
  • Normal ovaries and distal third of vagina
  • Three stages: ductal development, ductal fusion, and septal resorption (2)

Ductal Development

Normal:

  • By six weeks: embryos with undifferentiated gonads and identically paired Wolffian and Mullerian ducts. 
  • 6-8 weeks: bidirectional growth of Mullerian ducts in female embryos with superior aspect becoming fallopian tubes and inferior aspect forming uterus, cervix, and proximal 2/3 of vagina. Kidneys, ureters, and urinary bladder developing from ureteral bud which also arises from Mullerian ducts.

Normal

Ductal Development Normal

Abnormal:

  • Arrest at this stage leading to hypoplasia or agenesis of the uterus, cervix, and/or vagina.
  • Full development of only one duct resulting in unicornuate uterus.
  • 30-50% of MDA’s with urinary tract abnormalities, renal agenesis most common (3).

Agenesis/Hypoplasia

Vaginal

Ductal Development Vaginal

Cervical

Ductal Development Cervical

Fundal

Ductal Development Fundal

Combined

Ductal Fusion

Normal:

By 10 weeks: paired Mullerian ducts migrating inferiorly and medially, forming uterovaginal canal with midline septum.

Normal

Abnormal:

  • Complete or near complete failure of fusion resulting in uterus didelphys.
  • Partial lack of fusion resulting in bicornuate uterus.

Didelphys

Ductal Fusion Didelphys

Bicorinuate
Partial

Ductal Fusion Partial

Bicorinuate
Complete

Ductal Fusion Complete

Septal resorption

Normal:

9-12 weeks: uterovaginal septum beginning to resorb in bidirectional direction (5).

Normal

Septal Resorption Normal

Abnormal:

  • No septal resorption leading to septate uterus.
  • Partial septal resorption resulting in subseptate uterus or vaginal septum in the setting of a normal uterus.
  • Near complete septal resorption leading to arcuate uterus.

Septate
Subseptate

Septal Resorption Subseptate

Septate
Complete

Septal Resorption Complete

Arcuate

Septal Resorption Arcuate

Imaging Modalities

Hysterosalpingography (HSG)

  • Limited utility in characterizing Mullerian anomalies since only lumen visualized.
  • Pearls: divergent angle of less than 75 degrees between endometrial horns suggesting septate uterus and angle of greater than 105 degrees suggesting bicornuate configuration,
  • Pitfalls: overlap between these two entities with majority of cases falling within this range and masses such as adenomyomas or fibroids mimicking these findings (3).

Ultrasound (US)

  • 3D imaging useful for visualization of exterior surface of uterine fundus.
  • Pearls: imaging during secretory phase preferred when endometrium thicker.

Magnetic resonance (MR)

  • Modality of choice since external surface and internal architecture of uterus well depicted.
  • T2 weighted sequences for visualization of anatomy--ideally coronal and axial imaging planes prescribed from sagittal images, parallel and perpendicular to body of uterus.
  • T1 weighted sequences useful for identification of blood products.
  • Large field of view images enabling visualization of kidneys and ureters and any concurrent urinary tract anomalies.

Errors of Ductal Development

Agenesis or Hypoplasia: Mayer-Rokitansky-Kuster-Hauser Syndrome

  • Hypoplasia or agenesis of uterus and upper 2/3 of vagina.
  • 5-10% of MDA cases.
  • Occurring in 1 out of 4000 females, second most common cause of primary amenorrhea (9).
  • Often presenting as primary amenorrhea with normal external characteristics because ovaries functioning normally.
  • Rudimentary uterine tissue, if present, always caudal to ovaries which may be ectopic in location (8).
  • Once diagnosed, surgery enabling normal sexual function and reproduction occurring with assistance.

Agenesis

Vaginal and cervical agenesis

 Agenesis-vaginal 

Left renal agenesis in same patient

Agenesis left renal

Hypoplasia

Presumed fibroid (star) stable in size for 14 years and strand of tissue (arrow) which may represent rudimentary uterine tissue

Hypoplasia

Normal ovaries more superiorly in same patient

Hypoplasia normal ovaries

Unicornuate Uterus

  • Partial or complete hypoplasia of one Mullerian duct
  • Rudimentary horn, if present, may or may not have endometrial tissue and may or may not communicate with endometrial canal20% of MDA cases, renal anomalies most common with this MDA, usually ipsilateral to rudimentary horn (3).

Unicornuate

No Rudimentary Horn

Unicornuate no Rudimentary Horn

Rudimentary Horn without Cavity

Rudimentary Horn with Noncommunicating Caviy

Rudimentary Horn with Noncommunicating Cavity

Rudimentary Horn with Communicating Cavity

Rudimentary Horn with Communicating Cavity

Unicornuate Uterus without Rudimentary Horn

HSG of right unicornuate uterus with patent endometrial cavity and fallopian tube

Unicornuate Uterus Endometrial Cavity

T2 axial MR of left unicornuate uterus

Unicornuate uterus T2 axial MR

US of right unicornuate uterus

Unicornuate uterus US

Intrauterine pregnancy in same patient at later date

Unicornuate uterus Intrauterine pregnancy

Unicornuate Uterus with Rudimentary Horn

Right unicornuate uterus with rudimentary left horn attached by fibrous tissue (arrow), possible endometrial tissue (arrowhead), and no communication with right endometrial canal

Right unicornuate uterus Right Unicornuate Uterus Endometrial Tissue Right Unicornuate Uterus Fibrous Tissue

Errors of Ductal Fusion

Uterine Didelphys

  • Near complete failure of Mullerian duct fusion
  • Results in two endometrial cavities, cervixes, and proximal vaginas
  • 5% of MDAs (3)
  • Pearl: external uterine fundal contour distinguishing fusion failures from incomplete resorption of septum. Bicornuate and didelphys uteri with less than 5 mm myometrium above level of endometrial horns or apex of fundus located below level of horns

Septate

Uterine Didelphys Septate

Bicornuate

Uterine Didelphys Bicornuate

Bicornuate

Uterine Didelphys Bicornuate

Uterine Didelphys

Two endometrial horns (top)

Two cervixes (bottom), patient has two proximal vaginas more inferiorly (not pictured)

Uterine Didelphys Two endometrial horns  Uterine Didelphys Two cervixes

Different patient with fluid collection adjacent to obliterated right hemivagina (arrow), patient subsequently underwent right hysterectomy and salpingectomy

Uterine Didelphys Uterine Didelphys obliterated right hemivagina

Bicornuate Uterus

  • Incomplete fusion of Mullerian ducts at level of uterine fundus
  • Second most common anomaly for MDA infertility patients, accounting for 10% of MDA cases
  • Pearl: external uterine fundal contour distinguishing fusion failures from incomplete resorption of septum. Bicornuate and didelphys uteri with less than 5 mm myometrium above level of endometrial horns or apex of fundus located below level of horns
  • Pearl: Upper vaginal septa occuring in about 25% of cases and when associated with bicornuate bicollis configuration, difficult to distinguish from didelphys uteri

Septate

Bicornuate Uterus Septate

Bicornuate

Bicornuate Uterus Bicornuate

Bicornuate

Bicornuate Uterus Bicornuate

Bicornuate Uterus

Apex of fundus below level of uterine horns, two cervixes, and no vaginal septum

Bicornuate Uterus uterine horns Bicornuate Uterus uterine horns

Left renal agenesis in same patient


Bicornuate Uterus left renal agenesis

MR and HSG on same patient with wide divergence of endometrial horns on HSG (arc)

Bicornuate Uterus MR Bicornuate Uterus HSG

US on different patient with external surface of uterine fundus below level of endometrial horns (arrowheads)

Bicornuate Uterus Endometrial Horns Bicornuate Uterus Endometrial Horns

Errors of Septal Resorption

Septate or Subseptate Uterus

  • Normal external contour of uterine fundus
  • 55% of MDA cases, poorest reproductive outcome regardless of size of septum (3)
  • When complete, extending from uterine fundus through cervix
  • Pearl: external uterine fundal contour distinguishing fusion failures from incomplete resorption of septum.
  • Septate, subseptate, and arcuate uteri having 5 mm or more of myometrium above level of endometrial horns
  • Treatment: Surgical resection of septum
  • No residual septum or septum less than 1 cm considered optimal for reproduction

Septate

Uterus septate

Bicornuate

Uterus bicornuate

Bicornuate

Uterus bicornuate

Complete Septum

Septum extending from fundus through cervix

Septum extending from fundus through cervix

Same patient with findings more difficult to visualize on coronal CT reformats

Complete septum CT Complete septum CT

Subseptate Uterus

Normal external contour of uterine fundus and divergence of endometrial horns on short axis T2 MR and 3D US

Subseptate Uterus T2 MR Subseptate Uterus 3D US

Post Septate Resection

No residual septum or septum less than 1 cm considered optimal for reproduction

Post Septate Resection

1. 2.67 cm
2. 1.10 cm

Post Septate Resection

1. 2.81 cm
2. 0.98 cm

Preoperative MR (left)

Postoperative HSG (right) with improved septal abnormality

Post Septate Resection MR  Post Septate Resection HSG

Arcuate Uterus

  • Near complete septal resorption
  • May be normal variant
  • Mild broad indentation of fundal portion of endometrium
  • No defining depth to distinguish from broad septum (3)
  • Up to 3.9% of general population with no increased prevalence in high risk groups (7)
  • Pearl: external uterine fundal contour distinguishing fusion failures from incomplete resorption of septum.
  • Septate, subseptate, and arcuate uteri having 5 mm or more of myometrium above level of endometrial horns

Septate

Arcuate Uterus Septate

Bicornuate

Arcuate Uterus Bicornuate

Bicornuate

Arcuate Uterus Bicornuate

Arcuate Uterus

Same patient on MR and 3D US with subtle broad indentation of fundal portion of endometrium with normal external contour of uterine fundus

Arcuate Uterus MRArcuate Uterus 3D US

References

  1. Behr SC, Courtier, JL, Qayyum A. Imaging of Mullerian duct anomalies, Radiographics 2012:32(6)
  2. Robbins JB, Parry JP, Guite KM et al. MRI of pregnancy-related issues: müllerian duct anomalies. AJR Am J Roentgenol 2012;198(2):302–310.
  3. Trolano RN, McCarthy SM. Mullerian duct anomalies: imaging and clinical issues. Radiology 2004; 233(1):19–34.
  4. The American Fertility Society classifications of adnexal adhesions, distal tubal obstruction, tubal occlusion secondary to tubal ligation, tubal pregnancies, Müllerian anomalies and intrauterine adhesions. Fertil Steril 1988; 49:944–955.
  5. Olpin JD, Heilbrun M. Imaging of müllerian duct anomalies. Clin Obstet Gynecol 2009;52(1):40–56.
  6. Li S, Qayyum A, Coakley FV, Hricak H. Association of renal agenesis and mullerian duct anomalies. J Comput Assist Tomogr 2000;24(6):829–834
  7. Chan YY, Jayaprakasan K, Zamora J, Thornton JG, Raine-Fenning N, Coomarasamy A. The prevalence of congenital uterine anomalies in unselected and high-risk populations: a systematic review. Hum Reprod Update 2011;17(6):761–771.
  8. Hall-Craggs MA, Williams CE, Pattison SH, et al. Mayer-Rokitansky-Kuster-Hauser syndrome: diagnosis with MR imaging. Radiology 2013;269(3).
  9. Giusti S, Fruzzetti E, Perini D, Fruzzetti F, Giusti P, Bartolozzi C, et al. Diagnosis of a variant of Mayer-Rokitansky-Kuster-Hauser syndrome: useful MRI findings. Abdom Imaging. 2011;36:753–55.
  10. Fedele L, Bianchi S, Marchini M, Mezzopane R, DiNola G, Tozzi L. Residual uterine septum of less than 1 cm after hysteroscopic metroplasty does not impair reproductive outcome. Hum Reprod 1996; 11:727–729.