A Case of Acquired Angioedema with Low C1 Inhibitor (C1-INH) Associated with Splenic Marginal Zone Lymphoma.

BACKGROUND Angioedema is a vascular reaction of the soft tissues or mucosa, with localized increased permeability of blood vessels. Patients with late-onset angioedema without urticaria have an increased risk of non-Hodgkin lymphoma. We present a case of late-onset angioedema that demonstrates that it is sometimes necessary to treat an indolent malignancy to address the symptoms of a secondary condition. CASE REPORT A 68-year-old man presented to the Emergency Department with distressing swelling of his tongue and lips. No urticaria was observed and the remainder of the physical examination was unremarkable. The patient's past medical history included chronic thrombocytopenia for the last 1.5 years, which had been asymptomatic. Routine laboratory testing revealed pancytopenia. The patient was referred to the Oncology Department, where he was diagnosed with splenic marginal zone lymphoma. A careful review of the patient's past medical history revealed 3 episodes of soft tissue swelling of the lower limbs and 2 episodes of unexplained colicky abdominal pain. The patient was started on maintenance therapy of danazol, which prevented further episodes of angioedema. He later underwent splenectomy to improve his pancytopenia and to treat his lymphoma. In the postoperative period, the patient discontinued the danazol therapy. Three months after the splenectomy, he was asymptomatic and had not had any further angioedema episodes, and his laboratory values showed he was in remission. CONCLUSIONS In this case, late-onset angioedema with recurrent episodes of soft tissue swelling was associated with underlying hematologic malignancy. The patient's angioedema resolved when the malignancy was treated.