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

Locations

• 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
• Requires the use of ionizing radiation to the pelvis of women in their reproductive years and may not display the origin of the mass as well as US
• CT demonstrates mass containing fat, water density, frequently calcification (e.g. a  tooth)
• Rim-like calcification
• Fat-fluid level may be present, but is uncommon
• MRI
• Hyperintense fat on T1 within fluid of low signal intensity
• Hyperintense mass on T2

 Treatment

• 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

Complications

• 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

Dahnert 4th edition
Cystic Teratomas  eMedicineChad A Hamilton, MD, Edward Kost, MD,  Margarett C Ellison, MD