The preferred imaging method to evaluate the majority of adnexal cysts is ultrasonography, which can help characterize the cyst type. Common benign adnexal cyst types include simple, hemorrhagic, endometrioma, and mature teratoma (dermoid cyst). In this part 2 of a 4-part series on cystic adnexal pathology, we focus on imaging signs for, and follow-up of, endometriomas and mature teratomas.
Endometriomas are common, typically benign, cysts that produce homogenous, low-level internal echoes and a “ground glass” appearance on ultrasonography. No internal flow is apparent on color Doppler. The presence of tiny echogenic wall foci can distinguish an endometrioma from a hemorrhagic cyst.
Rarely, endometriomas may undergo malignant transformation. Usually this occurs with cysts greater than 9 cm and in patients aged 45 years or older. A malignancy often exhibits rapid growth or the development of a solid nodule with flow on color Doppler.
Although surgery remains the first-line management for women with symptomatic or enlarging endometriomas, there appears to be a role for sonographic observation, with continuous progestational treatment, in women with small (< 5 cm) asymptomatic endometriomas.
The Society of Radiologists in Ultrasound 2010 Consensus Conference Statement recommended1:
- Short-interval follow-up (6 to 12 weeks) in reproductive-aged women to ensure acute hemorrhagic cysts are not mistaken for endometriomas
- If not removed surgically, sonographic follow-up is recommended, with frequency of follow up based on patient age and symptoms and cyst size and characteristics.
In FIGURES 1 through 11 (slides of image collections), we present several cases, including one of a 25-year-old patient presenting with pelvic pain and dyspareunia who was later found to have bilateral endometriomas.
Mature cystic teratomas display several telltale signs on imaging, including:
- hyperechoic lines/dots (“dermoid mesh”) corresponding to hair/skeletal components
- “Rokitanski nodule” – a peripherally placed mass of sebum, bones, and hair
- posterior acoustic shadowing
- cystic or floating spherical structures
- no internal flow on color Doppler
Rarely, dermoid cysts may undergo malignant transformation. Usually this occurs in cysts greater than 10 cm and in patients aged 50 years or older. Internal flow on color Doppler, branching, or invasion into adjacent structures can indicate malignancy.
The traditional treatment for dermoid cysts is surgical. However, given the ability for accurate diagnosis with vaginal ultrasonography, there appears to be a role for sonographic observation in asymptomatic women with small dermoids.2
If the cyst is not surgically removed, the Society of Radiologists in Ultrasound 2010 Consensus Conference Statement recommended initial sonographic follow up at no more than 6 months to 1 year to ensure no change in size or internal architecture.1
In FIGURES 12 through 24 below (slides of image collections), we offer imaging from the case presentation and follow-up of a 19-year-old patient with pelvic pain who has a history of ovarian cystectomy for dermoid cyst, as well as 6 additional case illustrations.
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