Pseudodysplastic epithelial artefacts associated with oral mucosa CO2 laser excision: an assessment of margin status

Using a CO(2) laser beam for biopsy is compromised by thermal cytological artefacts that could be critical when assessing dysplastic changes, as they may simulate cytological atypia. This study examined wounds caused by CO(2) laser, evaluating their size and features, utilizing 25 Sprage rats randomly allocated to five groups: four glossectomized using a CO(2) laser at 3, 6, 9 and 12 W and a control group treated with a conventional scalpel. Samples were prepared in 4 microm sections, stained, and studied double-blind by two pathologists. The artefacts identified included cellular and nuclear polymorphism, nuclear hyperchromatism and loss of intercellular adherence; they were mainly located in the basal and suprabasal layers of the oral epithelium. Number of artefacts per specimen did not differ between experimental groups. The width of epithelial damage adjacent to the laser incisions revealed 298.7+/-150.7 microm of damaged tissue (range 100-750 microm), with no differences between low (3 W) and high wattages (6, 9 and 12 W) (X(i)-X(j)=41.6; 95% CI=-125.1 to 208.4). No changes were observed in the control group. CO(2) laser (3-12 W) generates epithelial damage that can simulate light dysplasia with atypias mainly affecting basal and suprabasal layers that may lead to erroneous therapy.