Endometrioma vs hemorrhagic cyst: 'ground glass' and repeat ultrasound strategy
Echographic patterns according to IOTA
According to the updated IOTA consensus (2026), endometrioid cyst is characterized by 'ground-glass' echogenicity — typical homogeneous echogenicity of the contents. Hemorrhagic cyst is described differently: threadlike structures (fibrin strands), blood clots, stellate or cobweb-like echogenicity; the clot may shift gelatinously with transducer compression.
Mixed echogenicity (different echogenicity types within a single locule) is more characteristic of dermoid cyst and requires expansion of the differential diagnosis.
Classic features of endometrioma
According to clinical guidelines (Holland, 2026), endometrioma classically appears as a uni- or weakly multilocular cyst with homogeneous low-level internal echosignals (ground-glass). The wall is typically smooth, with absence of vascularized papillary tissue on Doppler. Bilaterality and association with other pelvic signs of endometriosis support the diagnosis.
| Feature | Endometrioma | Hemorrhagic cyst |
|---|---|---|
| Echogenicity of contents | Homogeneous 'ground-glass' | Fibrin strands, clots, stellate/cobweb-like |
| Mobility of contents | — | Clot shifts gelatinously on compression |
| Wall | Typically smooth | [to be clarified] |
| Doppler (solid tissue) | No vascularized papillary tissue | [to be clarified] |
| Dynamics | Stability over time | [to be clarified] |
Diagnostic pitfalls
Endometrioma should not be diagnosed reflexively in every cyst with low-level echosignals. Hemorrhagic cyst, dermoid, and neoplasm may overlap in appearance — especially with atypical presentation or in older patients. The diagnosis of endometrioma is strengthened by: stability over time, concomitant deep disease, and absence of suspicious vascularized solid tissue.
Repeat imaging strategy
The main argument supporting endometrioma is stability of the lesion on follow-up observation, whereas hemorrhagic cyst tends to regress. Specific timing and intervals for repeat TVUS are not provided in the available fragments — [to be clarified] per local protocol/consensus.
Frequently asked questions
How does IOTA differentiate endometrioma contents from hemorrhagic cyst?
Endometrioma — homogeneous 'ground-glass' echogenicity; hemorrhagic cyst — threadlike fibrin structures, clots, stellate or cobweb-like echogenicity.
What on transducer compression confirms hemorrhagic character?
Blood clot may shift gelatinously with transducer compression — a sign of hemorrhagic cyst according to IOTA (2026).
What features strengthen the diagnosis of endometrioma?
Stability of the lesion over time, concomitant deep disease, and absence of suspicious vascularized solid tissue.
Is every cyst with low-level echosignals an endometrioma?
No. Hemorrhagic cyst, dermoid, and neoplasm may overlap in appearance, especially with atypical presentation or in older patients.
What does mixed echogenicity within a single locule indicate?
Contents with different echogenicity types within a single locule — a pattern characteristic of dermoid cyst (IOTA, 2026).