Vascularized Composite Tissue Transplant Pathology

Abstract

Throughout the past few decades, vascularized composite tissue allotransplantation (CTA) has been introduced as an option for limb replacement and reconstruction of tissue defects. The first successful hand transplant was performed in Lyon, France, in September of 1998. Subsequently, over 90 upper extremity transplants have been performed, making these grafts the most common form of CTA. These tissue grafts are complex in that they consist of a heterogeneous mixture of tissues, including skin, fat, muscle, nerves, lymph nodes, bone, cartilage, ligaments, and bone marrow. In addition, they are unique because the skin provides a visual assessment of how the graft is functioning and aids in the diagnosis of rejection. The aforementioned phenomenon is secondary to the fact that the skin demonstrates the highest immunological activity in the context of acute rejection and is the first tissue to display signs of rejection. Clinically, early cutaneous presentation allows immediate detection of acute rejection and is particularly essential given the absence of reliable serological or cellular markers indicative of composite tissue rejection.