Endometriosis: Ectopic endometrial glands outside of uterine cavity

Endometrioma: Cystic collection of mixed blood products

Diffuse low-level internal echoes in 95%

• ○
  

  Homogeneous ground-glass echotexture

  
  
• ○
  

  May see fluid-fluid level in endometrioma

  
  
• ○
  

  Often see increased through transmission

  
  
• ○
  

  Will typically not see acoustic streaming on grayscale or color/power Doppler due to marked viscosity

Endometrioma may look anechoic transabdominally

Cyst wall with variable appearance, may see peripheral echogenic foci due to cholesterol crystals

Avascular on color Doppler

• ○
  

  Caveat: Decidualization during pregnancy can lead to vascularization

MR

• ○
  

  T1WI: Homogeneous high signal

  
  
• ○
  

  T2WI: Shading is distinguishing feature

Cesarean section endometriosis

• ○
  

  Hypoechoic abdominal wall mass

Deep invasive endometriosis

• ○
  

  Scarring, aggressive implants

Hemorrhagic cyst: Resolves in 4-6 weeks

• ○
  

  Acute hemorrhage can mimic endometrioma

  
  
• ○
  

  Fibrin strands

  
  
• ○
  

  Resolves in 4-6 weeks

Dermoid cyst (mature cystic teratoma)

• ○
  

  Hyperechoic, dirty shadowing, tip of iceberg sign

  
  
• ○
  

  Fat-fluid level

Cystic ovarian neoplasm

• ○
  

  Typically postmenopausal

Infertility

Cyclical or chronic pain

Use highest possible frequency or coded harmonic imaging to differentiate low-level echoes from near-field artifacts

Avoid decreasing overall gain or TGC to “clean” real echoes

Vascularity in peripheral nodules on color Doppler may indicate malignant transformation (except in pregnancy)

Absence of sliding sign (uterus and bowel slide with gentle EV transducer pressure) suggests adhesions, a common finding in endometriosis