Labeling an Anterior Lower Uterine Segment Fibroid
Label this fibroid as "anterior lower uterine segment (LUS)" or "anterior lower segment intramural" if it's within the myometrium, specifying its relationship to the endometrial cavity and proximity to the cervix.
Anatomical Classification Framework
The anterior lower uterine segment is a well-recognized anatomical location that requires specific documentation 1. Based on the ACR Appropriateness Criteria guidelines, all fibroids must be located according to the FIGO classification system 2, 3, 4, which describes their relationship to:
- The endometrium (submucosal, intramural, or subserosal)
- The myometrium (depth of penetration)
- The uterine serosa (external surface relationship)
Specific Labeling Approach
For your described fibroid:
Primary Location Descriptor
- "Anterior lower uterine segment" - This is the anatomically correct regional designation 1
Secondary Classification Elements
Type classification:
- If the fibroid is within the myometrial wall but near the endometrial line: classify as "intramural" with notation of endometrial proximity
- If it distorts the endometrial cavity: classify as "submucosal" with percentage of intracavitary component 2, 5
- If predominantly toward the anterior surface: may have subserosal component
Distance specifications to include:
- Distance from the internal cervical os (since it's closer to cervix)
- Relationship to the endometrial stripe (since it's "on top of" the endometrial line)
- Whether it's anterior wall versus anterior-fundal junction
Clinical Significance of This Location
This specific location matters because:
- Lower segment fibroids have different treatment responses - they may not respond as well to uterine artery embolization compared to fundal fibroids 2
- Anterior LUS location can cause distortion preventing secure hysterotomy closure during cesarean delivery 6
- Proximity to cervix affects surgical approach and complication risk 7
- Lower segment intramural fibroids are strongly associated with increased cesarean delivery rates (adjusted OR 23.79) 8
Structured Reporting Template
Use this format:
Location: Anterior lower uterine segment
Type: [Intramural/Submucosal/Mixed]
Size: [Maximal diameter in cm]
Relationship to endometrium: [Distance in mm, or "abutting/distorting"]
Distance from internal cervical os: [Measurement in cm]
FIGO Classification: [Specific FIGO subtype]Common Pitfalls to Avoid
Don't label as:
- Simply "anterior" - too vague, doesn't specify the critical lower segment location
- "Cervical" - unless it's actually arising from cervical stroma 7
- "Fundal" - you've already excluded this
- Generic "intramural" without regional specification
Critical distinction: The anterior lower uterine segment overlying the bladder is a specific anatomical zone 1 that requires explicit documentation because it impacts surgical planning, delivery management, and treatment selection 2, 5, 6.
The 2022 ACR guidelines emphasize that fibroid location, along with size and number, provides essential pretreatment information 2, and the 2025 diagnostic guidelines mandate adherence to standardized structured reporting 3 to enable proper clinical management decisions.