Epithelial Dysplasia in Actinic Cheilitis: Microscopic Study of 70 Cases from Brazil.

To compare two grading systems of epithelial dysplasia-World Health Organization (WHO) and binary system (BS) -in actinic cheilitis (AC). Seventy cases diagnosed as AC in an Oral Pathology Laboratory from Brazil in the last 12 years were retrospectively retrieved, including the demographic data of each patient. All conventionally stained slides were reviewed, and epithelial dysplasia was evaluated by two independent observers using both WHO and BS grading systems. Data correlation was performed using kappa and chi-square tests (p < 0.05). Most patients were white men with a mean age of 57 years old and history of chronic exposure to sunlight. Most of the lesions were clinically described as whitish plaques with irregular surface located in the lower lip semi-mucosa. Most cases were microscopically graded as severe epithelial dysplasia and low-risk by both observers. The interobserver and intraobserver agreement between systems was slight. All reddish lesions were graded as severe epithelial dysplasia, showing an equal distribution between low and high-risk grading. Most ulcerated lesions showed severe epithelial dysplasia but was graded as low-risk of malignant transformation. Statistical significance was observed among the presence of "irregular stratification", severe epithelial dysplasia and high-risk lesions (p < 0.05) likewise among the presence of "loss of polarity of basal cells" and "drop-shaped ridges" (p < 0.05) with high-risk lesions. The absence of "increased mitotic figures", "dyskeratosis" and "keratin pearls" (p < 0.05) were strongly correlated to low-risk lesions. The presence of "hyperchromasia" was statistically significant with severe epithelial dysplasia (p < 0.05) as well the absence of "atypical mitotic figures" with low-risk lesions (p < 0.05). Although there was slight agreement between microscopic grading systems, microscopic analysis indicated that architectural epithelial changes individually may be the more reliable criteria to indicate the risk of malignant transformation in AC in both grading systems.