Diagnose This! (October 30, 2017)

What is your diagnosis?​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​   ​ ​     ​

The photomicrographs show high power images of an artery which can be discerned by the presence of a visible internal elastic lamina. This artery shows endothelial lifting and numerous subendothelial lymphocytes. The included immunoperoxidase stain is of CD8 which stains for cytotoxic T-cells (mostly) and nicely highlights the subendothelial lymphocytes. In short, these findings are consistent with intimal arteritis. As the background tissue showed findings of T-cell mediated rejection (not shown) and the patient’s donor-specific antibodies were negative, this likely represents T-cell mediated vascular rejection.