We report the first 2 cases of hepatosplenic T-cell lymphoma in adolescents diagnosed with autoimmune hepatitis under long-term treatment with azathioprine. Patients presented with fatigue, hepatosplenomegaly, and pancytopenia. The diagnosis could be confirmed performing biopsies of liver and spleen or bone marrow, which demonstrated infiltration of neoplastic T lymphocytes with the typical phenotype with both markers, CD56(+) and TCRγδ(+) Thus, these cases emphasize the need to constantly reevaluate the administered dose and duration of thiopurines for autoimmune hepatitis, especially in adolescents.
