Hepatosplenic T-cell lymphoma C86.1

Hepatosplenic T-cell lymphoma is a rare (<1% of non-Hodgkin's lymphomas) clinically aggressive systemic T-NHL derived from cytochemical T cells, mostly gamma/delta T cells (Li Yet al. (2021). Up to 20% of lymphomas are associated with chronic immunosuppression (Pro B et al. 2020).

The average age of patients is 38 years (16-60 years) (Wang Q et al. 2021).

Patients with hepatosplenic T-cell lymphoma usually present with B symptoms and cytopenias that may initially suggest acute leukemia. Hematophagocytic syndrome may also occur (Pro B et al. 2020). Patients present with extranodal disease involving the spleen, liver, and bone marrow; lymphadenopathy or leukemic washout is usually absent (Yabe M et al. 2018). Routine laboratory tests frequently reveal elevated lactate dehydrogenase (71.4%), liver dysfunction (42.9%), and decreased fibrinogen (35.7%) (Wang Q et al 2021).

Morphologically, it is a sinusoidally growing monomorphic infiltrate of medium sized cells with pale cytoplasm.

The immunophenotype of the tumor cells is CD3+,CD5-,CD8-, CD4-,CD56+.

The cells are positive for T cell receptor γδ negative granzyme B and mostly negative for TCR alpha/beta (αβ).

Gene mutations in oncogenic pathways have been identified that are likely involved in pathogenesis (and could be targets for therapy). The most common chromosomal aberrations associated with HSTCL are isochromosome 7qand trisomy 8, and most cases have mutations in genes involved in chromatin modification or the JAK-STAT pathway. Thus, mutations are found in STAT3 or STAT5B (activation of the JAK-STAT pathway), mutations in SETD2, IN080 and ARID1 (these are involved in chromatin modification).

Currently, there is no single standard of care for HSTCL patients, although several studies have found beneficial effects from allogeneic hematopoietic stem cell transplantation (Yabe M et al. 2018).

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