Fig. 2

PV histopathology. The "x" represents edema buildup between intraepidermal keratinocytes-also known as acantholysis- due to loss of adhesion between cells. Fluid will build up in these potential spaces when the chance arises. The bottom layer of cells (some have been circled) located underneath the edema are left intact and have been said to have a tombstone appearance. They represent the intact basal layer. Copyright © 2011 Michael Bonert (https://commons.wikimedia.org/wiki/User:Nephron)