PTLD Class 1997

Posttransplant Neoplasia

 

World Health Organization PTLD Classification of 2017
Category Examples Histopathology Immunophenotype Clonal Status Cytogenetic and Oncogene Abnormalities Comments
Non-destructive PTLDs Reactive plasmacytic hyperplasia (PH) Mainly small lymphocytes and plasma cells without architectural effacement Polyclonal B cells, plasma cells and T cells. Immunoblasts often EBV-positive although some cases of EBV negative FFH are included All are polyclonal or may have very small monoclonal B cell populations; IM may have clonal or oligoclonal EBV terminal repeat genes

PH has no abnormalities; IM and FFH may on occasion have nonspecific simple cytogenetic abnormalitieis Often regress with reduced immunosuppression or excision for localized cases, severe cases may be fatal. Criteria for differential diagnosis from other reactive lymphoid processes not well defined and depend on extent of proliferation, clinical correlation and presence or absence of EBV. May be followed by polymorphic or monomorphic PTLD
Infectious mononucleosis (IM) Mixed small lympohocytes, plasma cells and immunoblasts without architectural effacement
Florid follicular hyperplasia (FFH) Prominent hyperplastic germinal centers without architectural effacement
Polymorphic PTLD Older terms of Polymorphic B cell hyperplasia, Polymorphic B cell lymphoma are included in this catgegory Destruction of underlying architecture, full range of B-cell maturation seen, not fulfilling criteria for non-Hodgkin lymphoma; may have necrosis, scattered large bizarre cells (atypical immunoblasts), frequent mitoses, may have monomorphic areas Polyclonal B cells, may have monoclonal B cells; admixed T cells. Most are EBV positive Monoclonal B cells; (Rare cases may be polyclonal); non-clonal T cells Some have BCL6 somatic hypermutation (significance unclear) More common in children or following primary EBV infection; may contain uniform areas of transformed cells; Some cases regress with reduced immunosuppression, others may progress
Monomorphic PTLD B-cell neoplasms: Diffuse large B-cell lymphoma, Burkitt lymphoma, plasma cell myeloma, plasmacytoma, EBV-positive Marginal Zone lymphomas
T-cell neoplasms: Peripheral T-cell lymphoma, not otherwise specified, Hepatosplenic T cell lymphoma, other types
Fulfills criteria for non-Hodgkin lymphoma or plasma cell neoplasm; exception is indolent B cell neoplasms that are not included ()except for EBV positive MALT lymphomas Variable based on type of lymphoma it resembles; EBV is more variable than in other categories Clonal B cells and/or T cells, except for rare NK cell cases Frequent and heterogeneous; aberrant promoter hypermethylation and somatic mutation common; EBV negative cases frequently lack CDKN2A; possibly more frequent 11q abnormalities in EBV negative Burkitt lymphoma; findings differ from B cell lymphomas in HIV patients. Recommended to designate as PTLD then categorize further according to the type of lymphoma represented; A number of these malignancies (e.g., T/NK cell, pleomorphic diffuse EBV positive B cell lymphoma) are not classically "monomorphic", although that term continues to be used to segregate these from the first two categories above.
Classic Hodgkin Lymphoma Histologically identical to classic forms of Hodgkin lymphoma (does not include PTLD with Hodgkin-like cells in activated/neoplastic B cell background) Reed Sternberg cells in appropriate backgound fulfilling standard criteria for Hodgkin lymphoma; most often mixed cellularity type Classic HD CD15, CD30 pos; almost all are EBV positive< -- -- Since Reed-Sternberg-like cells can be seen in non-destructive, polymorphic and occasionally monomorphic PTLD, diagnosis requires appropriate morphologic and immunophenotypic features.

 


Reference
  • Swerdlow SH, Campo E, Harris NL et al., eds: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. IARC Press: Lyon, pp.453-462, 2017


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Last Modified: Tue Sept 25, 2018