Table 2.

Clinical and histological characteristics of the major PTCL subtypes.

Type of PTCL	Clinical characteristics	Histological features
PTCL-NOS	Most present with peripheral lymph-node enlargement, advanced disease and B symptoms	CD4 > CD8Antigen loss frequent (CD7, CD5, CD4/CD8, CD52)CD 10−, BCL6−, CLCX13−, PD1−
AITL	Patients are middle-aged and elderly and most present with generalised lymphadenopathy, hepatosplenomegaly. Laboratory findings include circulating immune complexes, cold agglutinins, and haemolytic anaemia	CD4+ or Mixed CD4/8 CXCL13+, PD1+Majority BCL6+Half are CD10+ Hyperplasia of follicular dendritic cellsEBV+ Bcell
ALK-positive ALCL	Male predominance (1.5 : 1) and occurs in the first three decades of life. Most patients present with advanced-stage disease, peripheral and/or abdominal lymphadenopathy. They often have B symptoms especially fever	CD 30+ALK translocation is present Majority EMA+ Majority CD2+, CD5+, CD4+, TIA1+, granzyme B+ Majority CD3−, CD8−
ALK-negative ALCL	Compared to ALK+ ALCL, patients are older (40–65 year-old) and the clinical course is more aggressive. Similar to ALK+ ALCL, patients present with advanced disease, peripheral and/or abdominal lymphadenopathy, and B symptoms	CD30+ (strong and homogenous staining) Majority CD3+, CD4+, CD 43+ Minority EMA+PAX5−EBV markers EBER and LMP1 negative