Blastic transformation after splenectomy in a patient with nonvillous splenic marginal zone lymphoma with p53 overexpression: a case report.

A 61-year-old man with no subjective symptom was admitted to our hospital for further examination of the causes of anemia (hemoglobin, 9.5 g/dL) and thrombocytopenia (platelets, 9.2 x 10(4)/microL), which had been pointed out in a medical checkup half a year previously. A bone marrow examination showed 73% lymphoid cells. Immunophenotyping of these cells were CD19+CD20+CD3-CD5-CD10-CD23-, and light chain restriction (kappa) was positive by fluorescence-activated cell sorting analysis. A computed tomography scan showed mild splenomegaly. To confirm the diagnosis histologically, we performed a splenectomy. Finally, we diagnosed the patient's disease as nonvillous splenic marginal zone lymphoma (SMZL). A month after the splenectomy, the white blood cell count was remarkably increased to 7 x 10(4)/microL with the blastic transformation of lymphoid cells. We first treated the patient with fludarabine and then with the CHOP regimen (cyclophosphamide, hydroxydaunomycin, vincristine [Oncovin], and prednisone), but the disease was so refractory that the patient died of the disease 13 months after the splenectomy. Immunohistochemical staining and a molecular examination for p53 were carried out with specimens from the splenectomy. We found overexpression of the p53 protein in lymphoid cells and a point missense mutation in codon 280 at exon 8 that changed AGA (Arg) to AGT (Ser). This case may indicate the existence of a more aggressive subset of SMZL, suggesting a reconsideration of the roles of splenectomy and p53 overexpression in the diagnostic and therapeutic approaches to patients with SMZL.