Epidermotropism

Epidermotropism

This is the seemingly directed movement of cells from the dermis into the lower third of the epidermis with the tendency to aggregate in collections or nests. Spongiosis is minimal or absent.

This term is used in the description of Mycosis fungoides where atypical T lymphocytes infiltrate into the lower epidermis forming Pautrier microabscesses.

The term can also be applied in tumour pathology to Melanomas and Mammary and Extramammary Paget's disease . Merkel cell tumour and SCC also show Pagetoid spread as nests but these cells originate in the epidermis rather than infiltrate into it.