Formerly known as dermoid cysts, mature cystic teratomas are the most common form of ovarian mass in women under age 45. They comprise about 20 percent of all ovarian germ cell tumors, reports StatPearls, and typically occur in premenopausal women. They can even be found in adolescents.
Although cystic teratomas are very rarely malignant, they do pose a risk of ovarian torsion, making prompt evaluation and potentially surgical removal essential aspects of care.
The Formation of a Common Ovarian Neoplasm
Mature cystic teratomas contain tissues developed from the ectoderm, mesoderm and endoderm layers of germ cells. Because of this, these tumors can contain developmentally mature skin, hair, sweat glands, nails, teeth, eyes, cartilage, blood, fat and even thyroid tissue. Most are smaller than 15 centimeters, reports StatPearls.
Although teratomas often cause no symptoms, some can result in acute pelvic pain. As noted, they also put patients at risk for ovarian torsion, which can lead to ovarian necrosis and infection.
Evaluating Mature Cystic Teratomas With Ultrasound
Careful imaging is key to identifying mature cystic teratomas and differentiating them from ordinary ovarian dermoid cysts. Although the two types of tumors can appear similar with imaging, as images from Radiopaedia demonstrate, there is a fundamental difference: Ovarian dermoid cysts are composed only of ectodermal elements, whereas mature cystic teratomas contain mesodermal and endodermal elements, as well.
For a mature cystic teratoma, ultrasound is the preferred imaging modality. Although these tumors can have a non-specific appearance that may make identification challenging, they do have some sonographic signs that can aid in diagnosis. According to research published in Insights in Imaging, the two most common signs of teratoma on ultrasound are increased echogenicity and a visible dermoid plug.
A Rokitansky nodule (dermoid plug) is the most common sonographic finding for mature cystic teratomas. It appears as a densely echogenic protuberance that projects into the cystic lumen. The acoustic shadowing it causes is usually due to the presence of hair, teeth and fat in the teratoma.
Diffuse or regional high-amplitude echoes are almost always present with a mature cystic teratoma. This increased echogenicity is due to the presence of mixed sebaceous material and hair in the tumor. It may be either diffuse or focal.
According to Radiopaedia, other sonographic signs to watch for include:
- "Tip of the iceberg" sign
- Dot-dash sign
- Fat-fluid or fluid-fluid level
- Floating balls sign
If there is secondary ovarian torsion, the characteristic whirlpool sign on ultrasound can help a physician identify it quickly and refer a patient for any necessary surgical intervention.
Diagnosing for Better Care
Although ultrasound is an efficient and effective way to evaluate a mature cystic teratoma, there may be instances where the images are inconclusive. If this is the case, a CT scan may be useful in confirming a diagnosis.
Depending on the size of the mature cystic teratoma and any accompanying symptoms, watchful waiting or surgical removal may be in order. By familiarizing yourself with the sonographic characteristics of these tumors, you can ensure timely diagnosis and guide patients to the appropriate course of action.
