Table 2.
Reasons for difficulty in depth of invasion measurement
| Reason | No. (percentage) | |
|---|---|---|
| 1 | Adjacent mucosa not present | 18/95 (20.2%) |
| 2 | Adjacent mucosa present in other sections, but absent in the section with the greatest thickness limiting accurate assessment of depth of invasion | 2/95 (2.8%) |
| 3 | Mucosa present on one side limiting assessment of horizon | 32/95 (44.4%) |
| 4 | Angulated adjacent mucosa (lip/retromolar trigone/alveolar tumour) or mucosa on both sides not in a straight line | 13/95 (13.9%) |
| 5 | Polypoidal tumour with uniform thickness | 15/95 (20.8%) |
| 6 | Irregular hyperplasia in adjacent mucosa with thick rete pegs leading to discrepancy in assessment of level of adjacent mucosa | 1/95 (1.4%) |
| 7 | Cut-off point of adjacent epithelium not clear (submucosal tumour) | 9/95 (12.5%) |
| 8 | Adjacent benign mucosa far away and cutoff point not clear due to zone of dysplasia | 15/95 (20.8%) |
| 10 | Adjacent mucosa is visible in a perpendicular direction to the surface of the tumour (in cases of lateral border of tongue tumours) | 26/95 (36.1%) |
| 11 | Adjacent mucosa very thin (DOI same as TT) | 31/95 (32.6%) |
| 12 | Rounded/arcuate horizon (based on the rounded natural contour of the tongue) | 26/95 (29.2%) |