Table 1 Differential diagnosis to Intestinal T cell lymphomas
NK-cell enteropathy | Indolent T cell LPD of the GI tract | EATL | MEITL | |
|---|---|---|---|---|
Epidemiology | Unknown | Unknown | Northern Europe | Asian, Hispanic |
Associations | Unknown | Unknown | Celiac, HLA-DQ2, HLA-DQ8 | Unknown |
Location | Stomach, small intestine, colon | Small intestine, colon, others | Small intestine | Small intestine |
Histology | Medium to large in size, with mild cytological atypia. Destruction of adjacent glands may be present at advanced stages Epitheliotropism is usually absent. | Small and monotonous lymphocytes, with none to mild cytological atypia. Non-destructive. Occasional epitheliotropism. | Pleomorphic. Medium to large with cytological atypia. Epitheliotropism is usually present. Angiodestruction may be present. | Monomorphic medium cells. Epitheliotropism usually present. |
Phenotype | cCD3 + a CD8- CD5- CD7 + CD4- CD56 + TIA1 + EBER(ish)- Granzyme B + Low Ki-67(< 25%) | CD2 + CD3 + CD5 ± CD7 ± CD8 + > CD4 + c CD56- TIA1-/ + Granzyme B- EBER(ish) - Low Ki-67 (< 10%) | CD3 + CD4- CD5- CD7 + CD8-/ + d CD56- CD103 + CD30 ± TIA-1 + , Granzyme B + High Ki-67 (> 50%) | CD3 + CD5- CD8 + > CD4 + CD56 + b CD30- CD103 + TIA1 + Granzyme B + EBER(ish)- High Ki-67 (> 50%). MATK + # |
TCR expression | Negative | Alpha beta (αβ) | Alpha beta (αβ) > gamma delta (ɣδ) | Gamma delta (ɣδ) > Alpha beta (αβ) |
Molecular | TCR polyclonal | STAT3-JAK2 fusion | STAT5B, JAK3, GNAI2 Gains of 1q and 5q | SETD2, STAT5B, JAK3, GNAI2 Gains of MYC |