Splenic marginal zone cell lymphoma involving liver and bone marrow. Report of a case with protracted follow-up, showing progressive disappearance of the lymphoma after splenectomy

We report the case of a 42-year-old man who presented with B-symptoms, moderate splenomegaly and multiple nodules in the liver. Histologically, lymphocytic infiltrates were seen in the portal spaces and sinusoids of the liver and in the paratrabecular areas of the bone marrow. After excision, the spleen showed minimal disturbance of architecture with an expansion of the follicular marginal zones. These findings were considered inconclusive for lymphoma and the patient was treated only with non-steroidal anti- inflammatory drugs for persisting fever. Five months after splenectomy, a bone marrow biopsy still showed diffuse lymphoid infiltrates. From then on, the patient's condition improved with no further evidence of disease. Ten years after splenectomy the case was reconsidered as a splenic marginal cell lymphoma, indolent variant. Immunohistochemical and gene rearrangement studies demonstrated the monoclonality of the splenic proliferation, supporting the diagnosis. A further bone marrow biopsy did not detect residual lymphoid infiltrates. This case confirms that splenic marginal zone cell lymphoma may have a deceptively favorable course, even when presenting at an advanced stage. Moreover, it indicates that extrasplenic localizations of the lymphoma may persist for a long while after splenectomy but may vanish over time without therapy.