What is the role of ultrasonography in the workup of endometrioma/endometriosis?

Updated: Dec 14, 2018
  • Author: Shawn Daly, MD; Chief Editor: Eugene C Lin, MD  more...
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Answer

Answer

Patients with suspected endometriosis referred for US scanning evaluation should receive a transvaginal study, because this is more sensitive for smaller endometriomas. [31, 32, 33, 34] The kidneys should be examined for hydronephrosis.

The typical US scan finding in endometriosis is a cystic mass with diffuse, low-level echoes. [35, 33] Punctate echogenicities in the wall may be present and increase diagnostic confidence. [36]

(See the images below.)

Endovaginal ultrasound scan of an endometrioma. No Endovaginal ultrasound scan of an endometrioma. Note the characteristic diffuse, low-level echoes of the endometrioma (E) giving a solid appearance.
Sagittal view shows an endometrioma (e) in the cul Sagittal view shows an endometrioma (e) in the cul-de-sac with diffuse, low-level echoes. The endometrioma lies directly posterior to the uterus (u).

However, endometriomas can vary in appearance. For example, they may appear cystic (simple or complex), or they may resemble a solid mass (see the image below). [36, 30] Punctate echogenicities in the wall of endometriomas are less commonly seen but add specificity to the diagnosis. [14]

Transverse view of a left ovarian endometrioma sho Transverse view of a left ovarian endometrioma shows a heterogeneous appearance, with diffuse, low-level echoes interspersed with echogenic and anechoic areas.

Small implants typically are not seen with US scanning. [2]

Doppler waveform analysis is not helpful in differentiating endometriomas from other masses. Low-resistance waveforms resembling malignancy are encountered in endometriomas. [19, 34]  (See the image below.)

Duplex ultrasound scan of an endometrioma. Note th Duplex ultrasound scan of an endometrioma. Note the resistive index of 0.48, indicating a low-resistance waveform. This value can also be seen with an ovarian neoplasm, yielding false-positive results.

In a study of ultrasound findings in women with decidualized endometriomas surgically removed during pregnancy, most endometriomas (14/17, 82%) were described as manifesting vascularized rounded papillary projections with a smooth contour in an ovarian cyst with one or a few cyst locules and ground-glass or low-level echogenicity of the cyst fluid. [37]


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