Lymphoma-associated paraneoplastic angioedema with normal C1-inhibitor activity: does danazol work?

A patient with splenic marginal zone lymphoma presented with severe, symptomatic acquired angioedema. Unlike previously reported cases, his serum levels of complement and C1 inhibitor (C1-INH) were not decreased. Nonetheless, he responded clinically to treatment with an attenuated androgen and, after therapeutic splenectomy, has been maintained asymptomatic without androgen therapy for 5 years. Thus stimulation of C1-INH synthesis may overcome paraneoplastic angioedema in patients with lymphoproliferative disorders despite the absence of typical evidence for a quantitative or qualitative defect in C1-INH. Androgens should not be withheld despite a normal level of C1-INH and complement in symptomatic patients.