Scheme of the dissecting aneurysm of the thoracic and abdominal aorta in an 84-year-old woman; (1) beginning of dissection, (2) end of dissection
Figure 9.2 shows histotopography (photo of the histological specimen – glass) of the part of the aortic wall with the adventitia and dissection of the media (stained with phosphotungstic hematoxylin).
Histotopography. Dissection of the media
Similarly, Fig. 9.3 shows dissection in the media, where blue color represents fibrin, which is a proof of blood flowing in the false lumen of the dissecting aneurysm.
Dissection of aortic media
Panarteritis is formed by a mixed inflammatory infiltrate composed of polymorphonuclear leukocytes, lymphocytes, and plasma cells.
Figure 9.4 (Kossa + HE staining) shows the intima and part of the media. In the intima an atherosclerotic plaque with calcium and deposits of calcium can be seen in the area of the internal elastic lamina, which is a typical sign of GCA.
Typical deposits of calcium salts in the area of the internal elastic lamina and atherosclerotic plaque with calcium in the intima (Kossa + HE staining)
The pathological-anatomical diagnosis and the cause of death were dissecting aneurysm of the ascending thoracic aorta continuing to the descending thoracic and abdominal aorta as far as the origin of the celiac trunk that developed due to giant cell arteritis.
An 81-year-old patient with a history of two myocardial infarctions with an implanted pacemaker was admitted to the hospital for intense pressure pain over a large area in the front part of the chest. ECG showed a pacemaker rhythm with a frequency of 70/min and the condition after anteroseptal and lateral myocardial infarction. The values of indicating enzymes of myocardium damage – CK, AST, and ALT – were normal, similarly as the blood count. Twenty hours of admission to the hospital, the patient had a sudden respiratory and cardiac arrest indicating another acute heart attack.
At the autopsy, a 4 cm long longitudinal tear was discovered at the posterior wall of the aorta 0.4 cm above the aortic valve. The tear created a sac between the adventitia and the media, 8 cm long, filled with about 150 ml of dark red clots. A 20 cm section of the adventitia of the ascending and descending aortas was filled with blood. Macroscopic image of the aortic arch shows a split aortic wall with blood clots (Fig. 9.5).
Dissecting aneurysm of the aorta
The histological features showed inflammation in the media composed largely of lymphocytes and a mixed inflammatory infiltrate, histiocytes, and giant cells in the adventitia (Fig. 9.6)
Typical multinucleated cells
The cause of the patient’s death was giant cell arteritis with a dissecting aneurysm of the ascending aorta. Clinically suspected fresh myocardial infarction was not confirmed by the autopsy.
An 86-year-old patient with a multiyear history of ischemic heart disease and duodenal ulcers, after anteroseptal myocardium infarction 2 years before, was admitted to the hospital for a pressure chest pain lasting for 2 h. At the time of admission, his blood pressure was 90/60mmHg, and the ECG showed acute myocardial infarction of the anterior wall. Urgent thrombolysis could not be carried out in the patient because of the melena finding probably due to bleeding from a duodenal ulcer. Eighteen hours after admission to the hospital, the patient suddenly died.
The autopsy revealed a fresh extensive myocardial infarction of the anterior and posterior walls of the left ventricle and of papillary muscles of the mitral valve. When examining the abdominal aorta, two circular (ringlike) widenings of the lumen (aneurysms) by about 0.5 cm and mural thrombi were observed below the level of the origin of renal arteries, and the common iliac arteries were extended in a balloon-like way having 1.2 cm in diameter (Fig. 9.7).
Scheme of aneurysm of the abdominal aorta and both iliac arteries in an 86-year-old man
One of the typical histopathological findings in GCA is a granuloma or a granulomatous inflammation of the media, as seen in Fig. 9.8 in the abdominal aorta in the 86-year-old patient (stained with HE).
Granuloma in the media of the abdominal aorta
The inflammatory infiltrate is composed predominantly of histiocytes and plasmatic cells, not so many lymphocytes, and one giant multinucleated cell.
In the area of the granuloma, the structure of elastic fibers disappears. All the arterial wall layers are involved, but most of them the media. The internal elastic lamina membrane is split and fragmented, as seen in Fig. 9.9, showing the same patient.
Split and fragmentation of the internal elastic membrane
Figure 9.10 shows another GCA typical histological finding, namely, multinucleated giant cells.
Typical multinucleated cells
Thus, aneurysms of abdominal aorta and lumbar arteries developed due to giant cell arteritis.
Involvement of the aorta and its branches is observed in about 10–15 % of GCA patients. The symptoms indicating involvement of large arteries include Raynaud’s phenomenon, paresthesia, and claudication in extremities. Aneurysmal dilatation of the root of the ascending aorta causes insufficiency of the aortic valve . In a group of 72 patients with involvement of the aorta and/or its branches in histologically verified GCA, the ascending aorta and the aortic arch were affected in 39 patients, the subclavian and the axillary arteries in 26 patients, and femoropopliteal arteries in 18 patients; 9 patients underwent amputation of an upper or lower extremity .
Involvement of the aorta can be life-threatening due to the development of a dissecting aneurysm or rupture of the aorta . In the group of 24 patients with a dissecting aneurysm of the aorta, reported in the literature, giant cell arteritis was for the first time diagnosed during autopsy as the cause of dissection of the aorta and the subsequent death in up to 46 % of patients . Similarly, both our patients with a diagnosis of a dissecting aneurysm had GCA diagnosis detected as late as during autopsy. Lie  reports in 18 patients with extracranial GCA the following causes of death: rupture of aortic aneurysm in 6 patients, dissection of aorta in 6 patients, cerebral infarction in 3 patients, and myocardial infarction in 3 patients. Säve-Söderbergh  describes the following causes of death in 9 GCA patients: two patients died of dissecting aneurysm of the aorta, another two of myocardial infarction, and five of sudden cerebral accident. None of the described patients was receiving adequate corticoid therapy.