Distinguishing angioimmunoblastic T-cell lymphoma from peripheral T-cell lymphoma, unspecified, using morphology, immunophenotype and molecular genetics.
OBJECTIVE
To identify distinguishing histological, immunophenotypic and molecular genetic features between angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma (PTL).


METHODS
Nodal T-cell lymphomas examined (n =137), included AITL (n = 89), PTL (n = 22), anaplastic large cell lymphoma (n = 16) and 'AITL/PTL indeterminate' (n = 10) with overlapping features between AITL and PTL, showing morphology typical of AITL but lacking follicular dendritic cell expansion. Immunohistochemistry for CD3, CD20, CD21 and CD10, in situ hybridization for Epstein-Barr virus encoded RNA (EBER) and polymerase chain reaction for T-cell and B-cell clonality analysis were performed.


RESULTS
Of the AITLs, 74/89 showed typical morphology, whereas 15/89 showed hyperplastic follicles. AITL and 'AITL/PTL indeterminate' showed a polymorphous infiltrate and prominent vascularity in all cases. In both groups, CD10 was present in the majority and clear cells and EBER positivity were specific (but not universal) features lacking in PTL. Detection of T-cell clonality was significantly higher in AITL (90%) compared with PTLu (59%).


CONCLUSIONS
Clear cells and EBV infection (when present) are useful distinguishing features and CD10 a sensitive and specific marker of AITL. Hyperplastic follicles are present in a significant minority of AITL. AITL/PTL indeterminate probably falls within the spectrum of AITL rather than PTL.
Attygalle
A D
AD
Department of Histopathology, The Royal Marsden NHS Foundation Trust, London, UK. ayoma.attygalle@rmh.nhs.uk
Chuang
S-S
SS
Diss
T C
TC
Du
M-Q
MQ
Isaacson
P G
PG
Dogan
A
A
D018951:Antigens, CD20 / Q000378:metabolism; D001402:B-Lymphocytes / Q000473:pathology; D017252:CD3 Complex / Q000378:metabolism; D002999:Clone Cells; D003937:Diagnosis, Differential; D015321:Gene Rearrangement; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007119:Immunoblastic Lymphadenopathy / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007150:Immunohistochemistry; D016130:Immunophenotyping; D016411:Lymphoma, T-Cell, Peripheral / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D015260:Neprilysin / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics; D017464:Receptors, Complement 3d / Q000378:metabolism; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000473:pathology
D018951:Antigens, CD20; D017252:CD3 Complex; D007143:Immunoglobulin Heavy Chains; D012367:RNA, Viral; D016692:Receptors, Antigen, T-Cell, gamma-delta; D017464:Receptors, Complement 3d; D015260:Neprilysin