Herein, we report on a patient with splenic marginal zone lymphoma who initially presented without splenomegaly and bone marrow (BM) or peripheral blood involvement. At first, the patient showed moderate leukothrombocytopenia; she was completely asymptomatic, and BM examination excluded a hematologic disease. After 7 months, spleen enlargement was detected without determining any symptoms or worsening of the bilinear cytopenia. Bone marrow histologic, immunohistochemic, cytologic, and immunophenotypic examinations were normal. Splenectomy was performed, and a diagnosis of splenic marginal zone B-cell lymphoma was established. A monoclonal IgVH gene rearrangement was identified in the spleen tissue (VH3 gene family) and subsequently detected in the BM mononuclear cells. Because of the large surgical debulking and the absence of histologic, cytologic, and immunophenotypic BM involvement, no further treatment was proposed. After the splenectomy, the blood cell count normalized, and neither BM nor peripheral blood involvement appeared after 12 months of follow-up.