Hepatosplenic T cell Lymphoma

Epidemiology and Etiology:

•  Young adults (15-30y)
• M > F
• History of chronic antigenic stimulation in the setting of immunosuppression:
• Whole organ transplantation
• Crohn disease

Common sites:

•  Spleen
• Liver
• Bone marrow
• Peripheral blood (only late in the course usually)

Gross features:

• marked hepatosplenomegaly
• Absence of lymphadenopathy

Histologic features:

•  marked sinusoidal infiltration of the spleen, liver, marrow

Immunophenotype:

Marker:	Sensitivity:	Specificity:
CD2, CD3
TCR gamma/delta
TCR ab (neg)
CD56	+/-
TIA-1
CD4 (neg)	Often
CD8 (neg)	Some positive
CD5 (neg)
CD7
Perforin (neg)	Generally
Granzyme B (neg)	Generally
CD25 (neg)

Molecular features:

• TRG@ rearrangement (biallelic in gamma-delta)
• TRB@ gene rearrangement (alpha-beta)
• i(7q) (consistently)
• 2 to 5 copies with disease progression
• Numerical and structural aberrations of the second chromosome 7 (disease progression)
• Ring chromosome leading to 7q amplification
• Trisomy 8 usually also
• Loss of a sex chromosome
• EBV negative (generally)

Other features:

•  Vast majority relapse after initial response to chemotherapy
• Median survival < 3y
• Rare long-term survival after bone marrow transplant

References:

o Jaffe ES. Pathobiology of peripheral T-cell lymphomas. Hematology Am Soc Hematol Educ Program. 2006:317-22.

• WHO Blue Book (2008)