Abdominal pain as a first symptom of iliac vein thrombosis.

Two patients are described with abdominal pain as a first symptom of primary iliac vein thrombosis. This phenomenon can be regarded to be analogous to the calf tenderness when thrombosis arises from the venous sinusoids in the calf muscles which is the usual localisation. When one is aware of this clinical entity, thrombotic occlusion will be recognized as the cause of the complaints, instead of being regarded to be a complication of another, yet unknown disease.