Introduction Hepatosplenic gamma delta T cell non-Hodgkin’s lymphoma (HSTCL) is an exceedingly rare entity in children. We hereby report two cases of HSTCL.

Case report 1 A 5-month-old boy was referred with a history of remittent high fever and progressive hepatosplenomegaly. He was a term twin born from an in vitro fertilized pregnancy. Blood examination revealed pancytopenia (hemoglobin 9.1 g/dl, white blood cell count 3200 mm³, and platelet count 90/mm³).

Diagnosis was established after a splenectomy with an immunohistochemic examination of the spleen. The tumor cells were positive for CD3, CD8. The proliferation index Ki 67 was 80–90%. The boy’s parents refused further chemotherapy and the boy died at the age of 11 months.

Case report 2 A 9-year-old boy had a progressive splenomegaly, mild hepatomegaly and thrombocytopenia. The bone marrow biopsy showed hypercellular marrow without atypical lymphoid cells. Splenectomy was performed due to progressive splenomegaly. An immunohistochemical examination showed atypical lymhoid cells, which were positive for Ki-67 and for the antigens CD3, CD8, CD57, CD45RO and TIA-1. A clonal T cell receptor gamma rearrangement has been demonstrated by PCR. The boy has been treated by NOPHO 95 protocol with an autologous bone marrow transplantation. He is in complete remission and in good clinical condition 26 months after diagnosis.

Conclusions Our patients differed from those reported in other HSTCL cases by having a younger age at diagnosis. HSTCL should be considered as a differential diagnosis in the cases of progressive splenomegaly in the absence of lymphadenopathy.