Inflammatory aneurysms of the abdominal aorta: Incidence, pathologic, and etiologic considerations

Specimen from inflammatory aneurysm. Border of adventitia and retroperitoneum. Note perivascular lymphocytic infiltrate. The retroperitoneal adipose tissue is infiltrated by chronic inflammatory cells and fibroblasts. (Hematoxylin-eosin stain; original magnification × 100.)

Specimen from inflammatory aneurysm. Photomicrograph at border of adventitia and retroperitoneum. The upper part of the photograph shows considerable inflammatory cell infiltrate and red cell debris. Note the striking fibrosis. (Hematoxylin-eosin stain; original magnification × 100.)

Specimen from ordinary atherosclerotic aneurysm. External border of adventitia. Note loose fibroconnective tissue with few inflammatory cells. (Hematoxylin-eosin stain; original magnification × 40.)