Splenic Marginal Zone Lymphoma in a Patient With Antiphospholipid Syndrome Treated With Rituximab: A Case Report.

Splenic marginal zone lymphoma (SMZL) usually presents with splenomegaly or symptoms related to cytopenia. We report a case of a 56-year-old female with previously diagnosed antiphospholipid syndrome (APS) on warfarin therapy who initially presented with abdominal pain and was found to have massive splenomegaly and splenic infarction on CT imaging. Initial clinical presentations and imaging findings were attributed to the subtherapeutic coagulation profile. The patient was later diagnosed with SMZL following workup for pancytopenia including bone marrow biopsy, flow cytometry, and PET scan. Cytopenias, splenomegaly, and abnormal metabolic activity in the spleen on the PET scan improved after treatment with four cycles of weekly rituximab. Our report presents a case of a patient with longstanding APS presenting with splenic infarction and pancytopenia who was subsequently diagnosed with SMZL and successfully treated with rituximab.