We report a 19-year-old woman who was presented with B-symptoms, massive splenomegaly, hepatomegaly and hypersplenism. She underwent diagnostic/therapeutic splenectomy. Microscopically, the spleen showed a vaguely micronodular and diffuse proliferation of lymphoid cells in the white pulp that also involved the red pulp. On immunohistochemical staining, this proliferation consisted predominantly of CD3(+), CD7(+) small T cells with the presence of a minor population of CD15(-),CD30(-), CD20(+) large atypical B cells. A liver biopsy also showed a similar morphology to that seen in the spleen. After splenectomy, only the pancytopenia improved. A combined immunochemotherapy regimen (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) was utilized, which resulted in a complete remission.