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Table of Contents
Definition / general | Clinical features | Microscopic (histologic) description | Immunohistochemistry | Molecular / cytogenetics descriptionCite this page: Luca D. Polymorphic PTLD. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphomanonBpolymorphicB.html. Accessed March 26th, 2019.
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
Immunohistochemistry
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
