A clinicopathological study of inflammatory abdominal aortic aneurysms: Relationship between clinical presentations and histological findings

Many authors have reported on so-called inflammatory abdominal aortic aneurysm (IAAA) clinically or histologically. However, there have been few reports associating both presentations. The purpose of this paper was to report the relationship between clinical data and histological findings of IAAA. We examined 10 cases of nonruptured IAAA. IAAA varied from the “scarring stage” to the “active stage” according to the clinical rank of inflammation based on C-reactive protein and/or erythrocyte sedimentation rate. Abdominal or back pain, and weight loss were common clinical symptoms in both stages, although they were observed more frequently in the active stage. Mantle sign was characteristic of the active stage. Patients with higher clinical ranks of inflammation were likely to have thicker adventitia although this difference was not significant. A significant correlation was observed between the clinical ranks of inflammation and histological scores of inflammatory cell infiltration in the aneurysmal adventitia. In most cases, white blood cell counts were within the normal range. Inflammatory cell infiltration was characteristic of the active stage and fibrous thickening of the adventitia was the most common character in both stages. Our data suggest that histologically diagnosed IAAA should correspond to the active stage of grossly diagnosed IAAA, and IAAA in the scarring stage will be histologically diagnosed as a noninflammatory atherosclerotic aneurysm.