COMPLETE RESOLUTION OF ACQUIRED ANGIOEDEMA FROM SPLENIC MARGINAL ZONE LYMPHOMA AFTER TREATMENT WITH RITUXIMAB

Abstract

<h3>Introduction</h3> Acquired angioedema (AAE) due to C1 esterase inhibitor (C1-INH) deficiency is clinically similar to hereditary angioedema (HAE), but typically develops in older patients. There is invariably an underlying disease such as a lymphoproliferative disorder, autoimmune condition, solid tumor, etc. that either drives autoantibody production against normal C1-INH and/or causes consumptive depletion of normally functioning C1-INH. <h3>Case Description</h3> A 68-year-old Caucasian male with past medical history of hypertension, presented 1 year previously with an episode of lip angioedema followed by recurrent episodes of abdominal pain lasting > 12 hours, associated early satiety, and gradual weight loss. He also developed peripheral neuropathy, splenomegaly of unclear etiology, and hypogammaglobulinemia. Workup of his angioedema led to the discovery of low C4 and C1-INH levels, and prophylactic treatment with Icatibant was initiated to treat further attacks. Given his age, splenomegaly, weight loss, and other clinically relevant information, he was evaluated for malignancy, especially lymphoproliferative disorders. He was subsequently diagnosed with Splenic Marginal Zone Lymphoma (SMZL), a clonal B cell neoplasia, and received one cycle of Rituximab with profound improvements of his angioedema-related symptoms, splenomegaly, and labs, including normalization of his quantitative C1-INH and C4 levels and hypogammaglobulinemia. <h3>Discussion</h3> Acquired angioedema in the form of C1-INH deficiency in older patients is often one of the initial manifestations of lymphoproliferative disorders and can present with prolonged episodes of abdominal pain. SMZL is highly associated with AAE, and prompt diagnosis and treatment of malignancy associated angioedema and other paraneoplastic manifestations can have a profound impact on clinical symptoms and quality of life.