What is the ultrasound description of a hemorrhagic corpus luteum cyst in a female of reproductive age?

Ultrasound Description of Hemorrhagic Corpus Luteum Cyst

A hemorrhagic corpus luteum cyst on ultrasound appears as a thick-walled cyst ≤5 cm with characteristic internal echoes showing a reticular (lace-like or spiderweb) pattern, a retracting clot with concave/angular margins, and peripheral vascularity on color Doppler with absent internal blood flow. 1

Classic Sonographic Features

The hemorrhagic corpus luteum demonstrates several pathognomonic characteristics that distinguish it from other adnexal masses:

Wall Characteristics

• Thick, smooth wall that may have crenulated (scalloped) inner margins 1
• Wall thickness typically <3 mm is considered benign 2
• The thick wall distinguishes it from simple follicular cysts 1

Internal Contents

• Reticular pattern with fine, discontinuous linear echoes creating a lace-like or spiderweb appearance throughout the cyst 1
• Retracting clot demonstrating straight, angular, or concave margins (not convex like solid tissue) 1, 2
• Avascular internal echogenic components that move with transducer pressure 1
• Internal echoes that are not solid tissue but represent blood products 1

Vascular Pattern on Color Doppler

• Intense peripheral vascularity surrounding the cyst (peripheral "ring of fire") 1
• Complete absence of internal blood flow within the hemorrhagic contents—this is critical for differentiating from solid components 1, 2
• Color Doppler flow visible only in surrounding ovarian tissue, not within the blood products 1

Size Considerations

• Typical hemorrhagic corpus luteum cysts are ≤5 cm in diameter in premenopausal women 1, 2
• Cysts ≤5 cm with classic features require no further management 1, 2
• Cysts >5 cm but <10 cm warrant follow-up ultrasound in 8-12 weeks to confirm functional nature 1, 2

Variations in Appearance

The corpus luteum can present with morphologic variations while remaining benign:

• Hypoechoic region in the ovary with peripheral flow but without a characteristic central cystic component 1
• Central cystic component with smooth thickened wall and avascular internal echoes 1
• Anechoic thick-walled cyst with intense peripheral vascularity 1
• Multiple corpora lutea may be present in cases of dual ovulation 1

Critical Diagnostic Pitfalls to Avoid

Do not misinterpret the retracting clot as a solid component—the key differentiating features are the concave margins (solid tumors have convex margins) and complete absence of internal vascularity on color Doppler 1, 2. The reticular pattern with fine linear echoes is pathognomonic for hemorrhagic content, not solid tissue 1.

In postmenopausal women, hemorrhagic cysts should not occur—if similar findings are seen in a postmenopausal patient, this requires referral to an ultrasound specialist or MRI for further evaluation, as the differential diagnosis changes significantly 2, 3.

Ensure complete evaluation with color Doppler—failing to use color Doppler may lead to misclassification of hemorrhagic contents as solid components, potentially resulting in unnecessary surgery 1, 2. The absence of internal vascularity is essential for confirming the benign nature of the internal echoes 1.

O-RADS Classification

Hemorrhagic corpus luteum cysts with classic features ≤5 cm are classified as O-RADS 2 (Almost Certainly Benign) with <1% risk of malignancy 1, 2. This classification applies only when all characteristic features are present: reticular pattern or retracting clot, peripheral vascularity, and absent internal flow 1, 2.