Proliferating pagetoid dyskeratosis: a new variant of pagetoid dyskeratosis associated with Bowen disease.

Pagetoid dyskeratosis refers to a characteristic pathologic aspect of keratinocytes of the epidermis and other stratified epithelia, that have a size larger than normal, a pale cytoplasm and a pycnotic nucleus surrounded by a clear halo. This aspect has been reported, often as an incidental finding, in benign conditions. We observed a case of Bowen disease featuring pagetoid dyskeratosis remarkable because the cells concerned were in mitosis, a finding so far unreported. We call this aspect "proliferating pagetoid dyskeratosis" to differentiate it from the usual pagetoid dyskeratosis and to highlight its association with mitotic nuclei. The significance of this rare finding warrants further study.