What does a stable lesion of mixed echogenicity in the left ovary, likely representing an ovarian (ovarian cystic teratoma) dermoid, mean?

Understanding an Ovarian Dermoid: Stable Lesion of Mixed Echogenicity

A stable lesion of mixed echogenicity in the left ovary favored to represent an ovarian dermoid is most likely a benign mature cystic teratoma with very low malignancy risk (<1%) that can be safely monitored with annual ultrasound follow-up if not surgically removed. 1

What is an Ovarian Dermoid?

An ovarian dermoid, also known as a mature cystic teratoma, is:

• A common benign germ cell tumor of the ovary
• Typically contains tissue from multiple embryonic layers (ectoderm, mesoderm, endoderm)
• Characterized by mixed echogenicity on ultrasound due to its varied contents:
  • Sebaceous material
  • Hair
  • Fat
  • Calcifications
  • Other tissues

Ultrasound Characteristics of Dermoid Cysts

Dermoid cysts have distinctive ultrasound features that allow confident diagnosis 1:

• Mixed echogenicity (areas of different densities)
• Hyperechoic components that may cause acoustic shadowing
• Hyperechoic lines and dots (representing hair)
• Fluid-fluid levels (from floating liquid fat)
• Floating echogenic spherical structures (pathognomonic but less common)

The term "stable" in your report is reassuring, suggesting the lesion has not changed over time, which further supports its benign nature.

Risk Assessment

According to the O-RADS (Ovarian-Adnexal Reporting and Data System) classification 1, 2:

• Typical dermoid cysts are classified as O-RADS 2 (almost certainly benign)
• Risk of malignancy is <1%
• Risk of malignant transformation is quite low, estimated at 1-2% 3, 4

Management Options

Conservative Management

• For typical dermoid cysts <10 cm:
  • Annual ultrasound surveillance is recommended if not surgically removed 1
  • Optional initial follow-up at 8-12 weeks may be helpful based on confidence in diagnosis 1

Surgical Consideration

Surgical intervention may be warranted if:

• The cyst is causing symptoms (pain, discomfort)
• The cyst is >10 cm in size
• There are changes in morphology or developing vascular components
• Patient is postmenopausal (higher risk of malignant transformation)

Surgical Approaches

If surgery is needed:

• Ovarian cystectomy (preserving normal ovarian tissue) is preferred in reproductive-age women 5
• Laparoscopic approach is typically used for smaller lesions
• Oophorectomy may be considered in specific situations, such as when malignancy is suspected 2

Important Considerations

Monitoring

• If conservative management is chosen, annual ultrasound follow-up is recommended 1
• Any changes in morphology or development of vascular components should prompt referral to an ultrasound specialist or MRI evaluation 1

Potential Complications

Though rare, be aware of possible complications:

• Torsion (twisting of the ovary)
• Rupture
• Infection
• Malignant transformation (1-2% risk) 3, 4

Special Situations

• Multiple dermoid cysts can occur within the same ovary or bilaterally 6
• Differential diagnosis includes other ovarian masses with mixed echogenicity

Conclusion for Your Case

The finding of a stable lesion with mixed echogenicity favored to be an ovarian dermoid is reassuring. The stability of the lesion suggests its benign nature. Management options include continued surveillance with annual ultrasound or surgical removal, depending on factors such as size, symptoms, and patient preference.