|Specialty Hematology and oncology|
Hepatosplenic T-cell lymphoma is a rare and generally incurable form of lymphoma.
Hepatosplenic γδ T-cell lymphoma
Hepatosplenic T-cell lymphoma is a systemic neoplasm comprising medium-sized cytotoxic T-cells that show a significant sinusoidal infiltration in the liver, spleen, and bone marrow.
This lymphoma is rare, comprising less than 5% of all cases, and is most common in young adults and adolescents. A distinct male gender preference has been described.
The cell of origin for this disease is an immature cytotoxic T-cell clonally expressing the γδ T-cell receptor. This disease is seen more often in immunosuppressed solid organ transplant recipients, an association that has led to the hypothesis that long-term immune stimulation in the setting of immunosuppression is the causative agent.
Cases of hepatosplenic T-cell lymphoma (HSTCL) have been reported in patients treated with the immunosuppressants azathioprine, infliximab and adalimumab. The majority occurred in patients with inflammatory bowel disease. Adolescents and young adult males were the major cohort of cases. They presented with a very aggressive disease course and, with one exception, died of the lymphoma. The FDA has required changes to the labeling to inform users and clinicians of the issue.
The typical clinical finding in a patient with hepatosplenic T-cell lymphoma is hepatosplenomegaly.
The constellation of thrombocytopenia, anemia, and leukopenia is common in patients with hepatosplenic T-cell lymphoma.
Sites of Involvement
The spleen and liver are always involved, with bone marrow involvement frequently present. Nodal involvement is exceedingly rare.
The neoplastic cells in this disorder show a monotonous appearance, with a small amount of cytoplasm and inconspicuous nucleoli.
Spleen and liver
This disease shows a distinct sinusoidal pattern of infiltration which spares the splenic white pulp and hepatic portal triads.
While the bone marrow is commonly involved, the detection of the neoplastic infiltrate may be difficult due to diffuse, interstitial pattern. Immunohistochemistry can aid in the detection of this lymphoma.
Cells of a similar morphology observed in solid organs are observed in peripheral blood.
The immunophenotype for hepatosplenic T-cell lymphoma is a post-thymic, immature T-cell.
Clonal rearrangement of the γ gene of the T-cell receptor is the hallmark of this disease. A few cases have shown rearrangement of the T-cell receptor β gene. Isochromosome 7q has been observed in all cases described so far, sometimes in conjunction with other chromosomal abnormalities such as trisomy 8.
CHOP frequently induces remission initially, but most patients relapse and die within two years. Autologous bone marrow transplantation is currently being investigated in the treatment of hepatosplenic lymphoma. Allogeneic bone marrow transplant has been proven to attain remission for over five years and possibly cure hepatosplenic lymphoma.