A not infrequent result of chronic glossitis is the occurrence of bluish-white or pearly patches or plaques on the surface of the tongue. As a rule they are smooth, but sometimes their surface is warty (Ichthyosis linguae). Referred generally to some irritating cause, they are frequently seen in smokers, but doubtless some are more predisposed than others. The papillae in the patches are almost if not quite obliterated, the epithelium is considerably altered, and there is an infiltration of round cells in the underlying tissues. The chief interest of this condition lies in the fact that very frequently epithelioma develops in a tongue so affected (see Fig. 385).

Fig. 385. - Cancer occurring in a tongue the seat of leucoplakia. (From a drawing by Dr, Alex. Macphail).