Learning Radiology xray montage
Dermoid Cyst of the Ovary

General Considerations

  • Dermoids, a term now used almost always interchangeably with teratomas, are tumors
    derived from more than one germ layer, frequently all three
    • As such, they can include hair, teeth, fat, skin, muscle, endocrine tissue
    • Ectodermal tissue predominates
  • Mature cystic teratomas are commonly referred to as dermoid cysts
  • They are the most common ovarian neoplasm
  • Mature cystic teratoma of the ovary is invariably benign
    • In rare cases (1-3%), they may undergo malignant change
      • The prognosis is generally poor for such malignant tumors
  • They can occur at any age
    • More common during reproductive years (16-55)
      • Peak incidence from 20-40
    • During adolescence, 50% of adnexal neoplasms are mature cystic teratomas


  • Ovary, most commonly
    • Bilateral from 8-25 % of the time
  • Teratomas may also occur in the
    • Mediastinum
    • Retroperitoneum
    • Cervical region
    • Brain

Clinical findings

  • Most frequently found incidentally during physical or radiographic examinations for other reasons
  • Symptoms, when present, include
    • Abdominal pain, usually constant and low-grade
    • Mass
    • Abnormal uterine bleeding
    • Back pain
    • Bladder and GI symptoms
      • Urinary frequency and change of bowel habits

Imaging Findings

  • Conventional radiography
    • Relatively insensitive, a conventional radiograph of the pelvis may identify
      • A soft tissue mass, if large enough
      • A fat-containing mass of lower density than the
        surrounding soft tissue, a finding which is diagnostic
      • Characteristic calcifications, such as
        • “Popcorn” calcifications in uterine fibroids
        • Rim-like calcifications in ovarian cystic lesions or
          sometimes uterine fibroids
        • A tooth or other bone (e.g. clavicle)
  • Ultrasound
    • Is the study of choice, either transabdominal or transvaginal
    • US has been reported to have a 98% positive predictive value
      for dermoids of the ovary
    • Complex mass with echogenic components
    • Mass itself is frequently echogenic producing “dirty acoustic shadowing”
    • May occasionally be purely cystic (9-15%) or purely solid (10-31%)
  • CT
  • MRI
    • Hyperintense fat on T1 within fluid of low signal intensity
    • Hyperintense mass on T2


  • Surgical removal can be accomplished with removal of the cyst
  • Spillage of the contents of the cyst is associated with increased risk of chemical peritonitis


  • Torsion is most common
    • The larger the tumor, the more likely the risk of torsion
    • Usually produces acute and severe pain
  • Rupture
    • Rare
    • May lead to shock, hemorrhage, or chemical peritonitis
    • Rupture often leads to the formation of fibrous tissue
    • Usually produces acute and severe pain
  • Infection
    • Rare
  • Autoimmune hemolytic anemia
    • Very rare

Differential Diagnosis

  • Benign or malignant ovarian neoplasm
  • Endometrioma
  • Tuboovarian abscess
  • Pedunculated uterine fibroid
  • Hydrosalpinx
  • Ectopic pregnancy
  • Pelvic kidney

Dermoid cyst of the ovary. A close-up view of the right lower quadrant from a conventional radiograph
of the abdomen and pelvis shows a cystic mass with a rim-like calcification (red arrows) containing fat density lower than that of the surrounding soft tissue. There is a calcification within the mass (blue arrow) which represents a tooth. This is a diagnostic appearance for a dermoid cyst of the ovary.
For additional information about this disease, click on this icon if seen above.
For this same photo without the arrows, click here

Cystic Teratomas  eMedicineChad A Hamilton, MD, Edward Kost, MD,  Margarett C Ellison, MD