Introduction: Graft monitoring following vascularized composite allotransplantation (VCA) relies primarily on serial skin biopsy. However, given that VCA comprised multiple tissue types, skin biopsy may not accurately reflect rejection in other transplanted tissue.
Methods: A review of the literature on episodes of both acute and chronic rejection following VCA was completed. Special attention was given to how these patients were monitored for rejection and whether skin biopsy accurately reflected the state of other tissue types within VCA.
Results: Following VCA, skin biopsies accurately reflected episodes of acute rejection, but chronic rejection, resulting in both muscle fibrosis and graft vasculopathy, did not present with any ostensible skin changes.
Conclusion: Various tissue types within VCA can reject at different times and rates. We define this phenomenon as "split rejection." Split rejection has significant implications on flap monitoring, as it suggests that skin biopsy alone may not be sufficient in monitoring long-term graft rejection.
Keywords: acute rejection; chronic rejection; immunosuppression; split rejection; vascularized composite allotransplantation.