Histopathological analysis of oral epithelial dysplasia in pericancerous epithelium of lingual squamous cell carcinoma of dogs and cats.

Oral epithelial dysplasia (OED) is a precancerous lesion of oral squamous cell carcinoma (SCC) in humans, characterized by decreased cytokeratin (CK) 13 expression, de novo CK17 expression, and increased Ki-67 expression. This study investigated the histopathological and immunohistochemical features of pericancerous epithelium (PCE) in lingual SCCs of dogs (n=14) and cats (n=8). PCEs were classified as high-grade or low-grade OED based on the human World Health Organization criteria. High-grade OED exhibited decreased CK13 expression, increased CK17 expression, and Ki-67 expression, resembling human high-grade OED. Morphological analysis revealed sharply demarcated lesions with drop-shaped rete processes and irregular epithelial stratification. These findings suggest that OED in canine and feline PCE shares key characteristics with human high-grade OED, supporting the presence of field cancerization in the oral mucosa of domestic animals.