From the Guidelines
The recommended initial imaging modality for a suspected dermoid cyst is ultrasound, specifically a combined transabdominal and transvaginal approach, as it is widely available, cost-effective, non-invasive, and does not involve radiation exposure. When performing an ultrasound for a suspected dermoid cyst, the characteristic appearance typically includes a well-defined cystic mass with heterogeneous internal echoes, often containing hyperechoic components representing hair, sebum, or calcifications 1. The "tip of the iceberg" sign may be present, where only a portion of the cyst is visible due to acoustic shadowing from dense contents. For dermoid cysts in the ovaries, transvaginal ultrasound offers better resolution than transabdominal approaches.
- Ultrasound has a reported sensitivity of 62.5% for dermoid cysts, as demonstrated in a prospective study on 74 patients evaluated with TVUS and MRI 1.
- If ultrasound findings are inconclusive or if complications such as torsion or rupture are suspected, MRI would be the next appropriate imaging modality, as it provides superior soft tissue contrast and can better characterize the fat content typical of dermoid cysts.
- CT scanning is generally avoided as an initial test, particularly in young patients and women of childbearing age, due to radiation exposure concerns.
- The O-RADS US risk stratification and management system can be used to guide the management of suspected dermoid cysts, with recommendations for follow-up and further characterization based on the size and characteristics of the cyst 1.
From the Research
Recommended Imaging Modality
The recommended initial imaging modality for a suspected dermoid cyst varies depending on the location and presentation of the cyst.
- For ovarian dermoid cysts, ultrasonography is recommended as the initial diagnostic modality due to its lack of ionizing radiation and ability to reveal unrelated pelvic pathology 2.
- For dermoid cysts in other locations, such as the nose, face, and scalp, imaging is usually performed before surgical intervention to determine the size, location, and extension of the cyst 3.
- For intracranial dermoid cysts, diffusion-weighted imaging (DWI) is considered a useful imaging modality for diagnosis and follow-up 4.
- In general, the choice of imaging modality depends on the specific clinical presentation and the need to determine the extent and relationships of the tumor 5.
Factors Influencing Imaging Choice
The choice of imaging modality may be influenced by several factors, including:
- The location of the cyst, with different modalities being more suitable for different locations 5, 2, 3, 4.
- The presence of orbital signs, which may indicate the need for preoperative imaging 6.
- The size and complexity of the cyst, which may affect the choice of imaging modality and the need for surgical intervention 6.