Pindborg J J, Reibel J, Roed-Peterson B, Mehta F S
Cancer. 1980 May 1;45(9):2330-6. doi: 10.1002/1097-0142(19800501)45:9<2330::aid-cncr2820450916>3.0.co;2-r.
A study of 112 biopsy specimens from Danish oral leukoplakia patients and 145 biopsy specimens from Indian leukoplakia patients revealed a chevron-like keratinization of the epithelium in a number of cases. Clinically, this type of keratinization was often characterized by a pumice-like appearance. The clinical and histologic changes were only observed in tobacco users, and appeared to be associated particularly with use of pipes, snuff, and hooklis.