| Feature | Criterion | Comment |
|---|---|---|
| Architecture | Volume percentage stroma <55% | Usually localised lesion, extending to diffuse |
| Cytology | Cytological demarcation | Change within localising lesion relative to background |
| Size | Exceeds 1 mm minimum diameter | Lesion extent defined by architecture and cytology |
| Exclusions | Cancer, polyps, secretory endometrium, artifact, etc | Careful review of differential diagnosis |