Figure 1. Patient 1: Excisional biopsy of the lymph node involved by polymorphous Post-transplant lymphoproliferative disorder. A - B. Histomorphologic findings of the lymph node biopsy reveal effacement of the nodal architecture (A. 40x) by a mixed proliferation of lymphocytes, immunoblasts, and plasma cells (B. 400x). C - F. Immunohistochemical studies highlight mixed T-cells (C. CD3), B-cells (D. PAX5), and polytypic plasma cells (E. CD138, F. Kappa, G Lambda). EBV EBER in-situ hybridization (H) highlights scattered EBV-positive cells.
Clonal B-cell rearrangement was demonstrated by the presence of a discrete peak following PCR with primers specific for the JH immunoglobulin heavy chain locus. In addition, PCR revealed prominent polyclonal background.
Concurrent bone marrow biopsy demonstrated normocellular marrow for age with infiltration of abnormal lambda light chain-restricted plasma cells (6% of all cells), small B-lymphocytes (18% of all cells), and T-cells (12% of all cells) consistent with marrow involvement by the PTLD, involving about 30% of all marrow (Figure 2 ). Histologic findings in the bone marrow resemble the lymph node. Cytogenetic studies, performed on the bone marrow aspirate, showed an abnormal female chromosome analysis comprised of two clones. 108