Female, 30 years, pregnant. Mole of skin of back.
There is some mitotic activity and there are some reactive changes, possibly due to repeated microtrauma (the skin of the back is not uncommonly exposed to friction or other physical influences). A small numer of mitotic figures may be envcountered in all types of naevus; there appear to be commonest in young adult females and especially during pregnancy.
Glatz et al., Am J Dermatopathol 2010; 32: 643-9.