Figure 2.

A: An illustration of the multiple concentric onion-skin pattern of the FVIII-r.ag-positive cells in a concentric-obliterative lesion (arrow). On the left is a conglomerate of positively stained endothelial cells, consistent with a partial slice through a plexiform lesion (arrowhead). B: For contrast, an adjacent section is stained for MSA. Note that the positive endothelial cells of the concentric-obliterative lesion do not stain with MSA (curved arrow). The surrounding smooth muscle coat is positive for MSA and negative for FVIII-r.ag. Also note that the plexiform lesion on the left is now more apparent in this deeper cut (arrowhead).