Types of Ulcer Edges
Ulcer edges are classified into distinct morphologic patterns that provide critical diagnostic information: regular/smooth edges characterize benign processes, while irregular/elevated/undermined edges suggest malignancy or specific infectious etiologies.
Benign Ulcer Edge Characteristics
Regular and clearly demarcated edges are the hallmark of benign ulceration across anatomic sites 1, 2:
- Smooth, regular contours with even borders that are well-defined and symmetric 2
- Tapered edges where surrounding tissue gradually transitions to the ulcer crater 2
- In gastric ulcers specifically, benign edges appear clearly demarcated with regular shapes 2
- Oral aphthous ulcers demonstrate well-defined erythematous borders surrounding the central crater 3, 4
Malignant Ulcer Edge Characteristics
Irregular, elevated, or asymmetric edges strongly suggest malignant transformation and require immediate biopsy 1, 2:
- Irregular or asymmetric edges that lack the smooth contour of benign lesions 2
- Elevated edges rising more than 1 mm above the surrounding mucosa 1
- Angulated or geographic shapes at the ulcer margin 2
- Overhanging or rolled edges where the ulcer margin projects over the base 1
Infectious Ulcer Edge Patterns
Undermined edges are pathognomonic for specific infectious etiologies, particularly tuberculosis 5, 4:
- Stellate ulcers with undermined edges and clear boundaries characterize tuberculous ulceration 5, 4
- The undermined quality means the edge extends beneath intact overlying tissue, creating a pocket 5
Inflammatory Bowel Disease Edge Morphology
Oedematous and overhanging edges develop in Crohn's disease as ulcers progress 1:
- Early aphthous ulcers have relatively normal surrounding mucosa 1
- As ulcers enlarge and coalesce, they develop overhanging oedematous mucosal edges 1
- Deep serpiginous or linear ulcers with these overhanging edges create the classic cobblestone appearance when islands of non-ulcerated mucosa remain 1
Clinical Application Algorithm
When evaluating any ulcer, systematically assess edge morphology 5, 4:
- Document edge regularity: smooth/regular versus irregular/asymmetric 2
- Measure edge elevation: flat versus raised >1 mm 1
- Assess for undermining: probe gently to detect pockets beneath intact tissue 5
- Note surrounding tissue: tapered transition versus abrupt demarcation 2
Critical Diagnostic Pitfalls
Never rely solely on edge morphology without biopsy for persistent or atypical ulcers, as this delays identification of malignancy with direct mortality impact 5, 4:
- Any chronic ulcer (>2 weeks) with irregular or elevated edges requires biopsy regardless of clinical suspicion 5, 4
- Inadequate biopsy technique that samples only the ulcer base without including the edge misses diagnostic features 5
- Benign-appearing edges do not exclude malignancy in high-risk patients or anatomic locations 2