Lymphoma & related disorders
Posttransplant lymphoproliferative disorders (PTLD)

Topic Completed: 1 September 2011

Minor changes: 5 July 2020

Copyright: 2002-2021,, Inc.

PubMed Search: Polymorphic PTLD

Dragos C. Luca, M.D.
Page views in 2020: 556
Page views in 2021 to date: 25
Cite this page: Luca D. PTLD-polymorphic. website. Accessed January 20th, 2021.
Definition / general
  • Morphologically polymorphic lesions composed of immunoblasts, plasma cells and small and intermediate sized lymphoid cells that efface the architecture of lymph nodes or form destructive extranodal masses and that do not fulfil the criteria for any of the recognized types of lymphoma described in immunocompetent hosts (WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, 4th Edition, Lyon 2008)
  • P-PTLD: polymorphic versus M-PTLD: monomorphic
Clinical features
  • Variable frequency: 20 - 80% of all PTLD
  • Most common pediatric PTLD
  • May regress after reduction in immunosuppression or may progress to lymphoma
Microscopic (histologic) description
  • Architectural effacement but full range of B cell maturation from immunoblasts to plasma cells and variable sized lymphocytes
  • May have geographic necrosis, HRS-like cells, numerous mitoses
  • Some may have monomorphic appearing areas - may suggest a continuous spectrum between P and M-PTLD
  • May have bone marrow lymphoid aggregates of unknown significance (P-PTLD > M-PTLD; children > adults), not always EBV positive
  • B cells with (~50%, also by flow cytometry) or without light chain restriction and heterogeneous T cells
  • Light chain restriction may be focal or different clonal populations may be present simultaneously
  • RS-like cells (when present): CD30+, CD20+ but CD15-
  • EBV (EBER) positive
  • Ki67 may be high
Molecular / cytogenetics description
  • Clonally rearranged Ig genes but clones less prominent than M-PTLD
  • EBV terminal repeat analysis - most sensitive method for clonal populations in EBV+ cases
  • Tumors at different sites may be clonally distinct
  • 75% of P-PTLD have Ig Variable mutations; no significant T cell clones
  • CGH: some recurrent abnormalities also seen in M-PTLD
  • May have BCL6 somatic hypermutations
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