Posttransplant Lymphoproliferative Disorders

Table 2

Clinicopathologic features of major types of posttransplant lymphoproliferative disorders.

	Early lesions (plasmacytic hyperplasia and infectious mononucleosis-like)	Polymorphic PTLD	Monomorphic PTLD
(i) Clinical features
(a) Age	Children and young adults	All age groups	All age groups
(b) Organ involved	Tonsils or lymph nodes	Lymph nodes, GIT, lung or allograft	Lymph node, any extranodal site, including bone marrow
(c) Regression	Usually regress either with minimal reduction of immunosuppressive drugs or spontaneously	Some cases regress, others progress	Very rare. Most cases progress rapidly
(ii) Histopathological features
(a) Tissue architecture	No or partial effacement	Nearly complete effacement	Complete effacement
(b) Nature of infiltrate	Comprised mainly of plasma cells and lymphoplasmacytoid cells in plasmacytic hyperplasia, and immunoblasts and plasmablasts in infectious mononucleosis-like lesion	Composed of a mixture of plasma cells, small lymphocytes, and large activated cells	Monotonous, similar to that of usual type B-cell NHL
(c) Atypia	Absent	Present/absent in large cells	Present
(d) Necrosis	Absent	Variable	Present (geographic)
(iii) Molecular features
(a) Ig gene	Polyclonal in most cases	Usually monoclonal; may be oligo or polyclonal	Monoclonal
(b) EBV	Usually nonclonal	Clonal	Clonal
(c) Structural alterations of oncogenes and TSG	Usually absent	Usually absent	Usually present

Ig: immunoglobulin, EBV: Epstein-Barr virus, PTLD: posttransplant lymphoproliferative disorder, NHL: non-Hodgkin’s lymphoma, TSG: tumour suppressor gene.