SALIVARY-GLAND DUCT INVOLVEMENT IN ORAL EPITHELIAL DYSPLASIA AND SQUAMOUS-CELL CARCINOMA

The clinical implications and prognostic significance of oral dysplast ic or cancerous epithelium involving salivary gland ducts have not bee n previously investigated. Screened routine tissue sections of 1216 ca ses of oral epithelial dysplasias and squamous cell carcinomas reveale d 26 examples (2.14%) that exhibited unequivocal ductal involvement. D uctal involvement was more likely to occur in floor of mouth lesions a nd in lesions exhibiting severe dysplasia or carcinoma in situ. Clinic al follow-up on 23 cases showed that the recurrence rate of the preinv asive lesions that exhibited ductal involvement was equal to that of t he squamous cell carcinomas. The depth of ductal dysplasia did not cor relate with recurrence rate. These results suggest that the involvemen t of salivary gland ducts by oral epithelial dysplasias and carcinomas in situ is an uncommon but significant finding. Surgical stripping or ablation of such lesions should extend at least 3 mm below the surfac e to ensure eradication of these reservoirs of dysplastic cells.