Splenic marginal zone lymphoma in 5 dogs (2001-2008)

Background: Splenic marginal zone lymphomas (MZL) in dogs arise from the marginal zone of B-cell follicles and can progress slowly.Objectives: To describe clinical features, treatment, and outcome of dogs with splenic MZL.Animals: Five dogs with naturally occurring MZL.Methods: Clinical, laboratory, and follow-up data were retrospectively reviewed. Diagnosis was based on clinical, histopathological, and immunophenotypic features.Results: All dogs had stage IV disease; among them, 2 were symptomatic (substage "b") because of splenic rupture. Four dogs underwent splenectomy and adjuvant doxorubicin, and 1 dog underwent surgery only. Three out of the 4 dogs treated with surgery and chemotherapy died of causes unrelated to lymphoma, after 760, 939, and 1,825 days, whereas the remaining dog was alive and in complete remission after 445 days. The dog not receiving any adjuvant treatment had recurrence of the tumor after 180 days.Conclusions and Clinical Importance: Splenic MZL appears indolent and can benefit from splenectomy, with or without systemic chemotherapy.