NCIt definition : An early post-transplant lymphoproliferative lesion characterized by immunoblastic
proliferation and paracortical expansion as seen in infectious mononucleosis. There
is architectural preservation of the involved tissues. Oligoclonal or monoclonal cellular
populations have been detected in a small number of cases. In some cases, a polymorphic
or monomorphic post-transplant lymphoproliferative disorder may follow this early
lesion.;