[Surgical treatment of "inflammatory" aneurysms of the abdominal aorta]

Two cases of "Inflammatory" aneurysm of the abdominal aorta and a review of this type of lesion were presented. The incidence of inflammatory aneurysm of the abdominal aorta in the literature is 2.5 to 15%, but there were no detail reports concerning with this in Japan. The pathogenesis is not clear, but it is evident both macroscopically and microscopically that the inflammatory aneurysms are different from athelosclerotic ones. They are characterized by perivascular peel of inflammatory fibrous tissue. It is possible that this type of aneurysms are merely a variant of Takayasu's disease. Until recently, the diagnosis of this type of aneurysm has not been made before surgery. The symptom of abdominal pain, weight loss, elevated ESR in a patient with abdominal aortic aneurysm are highly suggestive an inflammatory aneurysm. Characteristics of CT scan lead to more frequent preoperative diagnosis of inflammatory aneurysms of the aorta. It reveals a thickened often calcified aortic wall surrounded by a soft tissue mantle. Dynamic scanning shows an enhancing perianeurysnal mass. Graft replacement in these patients is often difficult and associated with increase in morbidity and mortality. At surgery, no attempt should be made to mobilize adjacent viscela in order to avoid injury. Arterial control should be obtained with as little as possible dissection. Some reports refer to successful steroid therapy resolving the inflammatory process and alleviating symptoms. Further research may resolve the treatment of choice for this type of lesion and optimize the timing of surgery.