T Cell

Question 1

Angioimmunoblastic T cell

Answer 1

Branching high endothelial venules
IHC: pan T cell, helper T cell (CD10, CD278, BCL6, CXCL13, CXCL5, ICOS). Helper T cells are CD4.
Trisomy 3, 5, X and 1p. EBV positive.

Question 2

Anaplastic large cell, ALK positive or negative

Answer 2

ALK positive, young and cells are small or lymphohistiocytic or pleomorphic or Hodgkin like.
ALK negative IRF4 or TP63 or triple negative with hallmark cells.
IHC: CD30 positive, T cell markers (10% to 20% null), CD45.

Question 3

Peripheral T cell

Answer 3

T cell markers, may have loss of CD3 or CD7. Mostly alpha beta.

Question 4

Extranodal natural killer T cell

Answer 4

NK: CD2. CD56 with expression of TIA-1, granzyme B and perforin. CD3 negative. EBV positive.

Question 5

Subcutaneous paniniculitis T cell

Answer 5

Cytotoxic T-cell profile: CD2, CD3, CD5, CD7, CD8, TIA-1, granzyme B.

Question 6

Hepatosplenic T-cell

Answer 6

Alpha beta and gamma delta types (majority)
Thiopurine, solid organ transplant, infliximab.
Infiltrates sinuses.
Non activated cytotoxic cell: TIA-1 positive, granzyme M positive, B is negative.