Intestinal angioedema caused by an acquired C1 esterase inhibitor deficiency associated with underlying splenic marginal zone lymphoma.

A 75-year-old woman presented with recurrent abdominal pain and vomiting for 1 year and was later found to have splenomegaly and pancytopenia. This case report depicts a clinical picture of intestinal angioedema, a challenging diagnosis, and an underlying rare syndrome of acquired C1 esterase inhibitor deficiency associated with splenic marginal zone lymphoma.