There were many dyskeratotic cells characterized by aggregation of tonofilaments and decrease in desmosomal tonofilament attachments. The dyskeratotic products which consist of aggregated tonofilaments and nuclear substances, and cells containing such materials, probably correspond to what is called "individual cell keratinization." They may be produced as a result of abnormal cell division of dyskeratotic cells.
Seiji M, Mizuno F. Electron Microscopic Study of Bowen's Disease. Arch Dermatol. 1969;99(1):3-16. doi:10.1001/archderm.1969.01610190009003