|S/no.||Diagnostic points and pitfalls|
|1.||Polymorphic ID-LPDs often show effacement of architecture but do not meet diagnostic criteria for standard lymphoma subtypes.|
|2.||In the non-transplant context (eg, patients with rheumatoid arthritis receiving methotrexate), the presence/significance of immunosuppression may not be clinically recognised and a detailed history not provided.|
|3.||Occurrence of CD30 and EBV positivity in the large cells without recognising the presence of concurrent positive small-to-medium-sized cells may mislead the pathologist to diagnose a polymorphic PTLD as CHL.|
|4.||Anti-CD20 therapy may have been previously given to patients with suspected PTLD. Loss of CD20 positivity should be closely correlated with such history and other B-cell markers and cannot in isolation be assumed to represent genuine absence of a B cell phenotype.|
CHL, classical Hodgkin lymphoma; EBV, Epstein-Barr virus; PTLD, post-transplant lymphoproliferative disorders.