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A 70-year-old woman was admitted to the hospital with a 3-year history of progressively reduced general health, vertigo, joint pain and exertional dyspnoea. Physical examination revealed a reduced general health status, a 3/6 systolic murmur at the aortic valve area, a dry cough and pitting oedema of both ankles. Abnormal laboratory parameters included an elevated C-reactive protein (71.7 mg/L; normal <5 mg/L) and hypochromic normocytic anaemia (haemoglobin 7.1 mmol/L, normal 7.6–9.5 mmol/L; mean corpuscular haemoglobin 1.59 fmol, normal 1.74–2.05 fmol). Echocardiography displayed pericardial effusion that was punctured, detecting granulocytes, macrophages and mesothelial cells in cytological analysis. Radiographs of the large joints showed diffuse symmetric osteoplastic changes. 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) depicted infiltration of the thoraco-abdominal aorta, short occlusion of the left subclavian artery and stenosis of both renal arteries with slightly raised glucose metabolism in the corresponding vessels. Furthermore, symmetric raised bone metabolism of the long bones of the upper and lower extremities, numerous ribs, backbone, pelvis, clavicles, acromions and the skull was demonstrated (figure 1A).
Clinical and imaging findings were suspicious for large-vessel vasculitis (LVV). An immunosuppressive therapy with prednisolone (30 mg/day) was initiated. Because of progressive weakness of the patient's thighs and lower leg oedema, prednisolone dose was increased and azathioprine (2 mg/kg body weight) was added, leading to a stable state of health with moderately increased inflammatory markers. In the further course, however, the patient’s general state worsened dramatically with development of paresis of both legs and loss of bladder and bowel control. MRI of the spinal column detected spinal ischaemia as causal factor. Thoraco-abdominal CT-angiography showed progressive aortitis, stenosis of the iliac and renal arteries, coeliac trunk and superior mesenteric artery (figure 1B) with rapidly approaching mesenteric ischaemia. Bypass surgery was tried to improve the blood circulation. Unfortunately, the patient died of septic shock with multiple organ failure.
An autopsy was done to clarify the nature of generalised vasculitis that was not entirely explained from the clinical feature. The histological analysis revealed multilocular inflammatory changes of the whole aorta (figure 2A) and adjacent large vessels, renal pelvis, perivascular area of the lungs, subdural area and the spinal column, which was specific for Erdheim-Chester-disease (ECD).1 ,2 The adventitia of the aorta appeared fibrotic with accumulation of foamy macrophages with CD68- (figure 2B), S-100- and PGM1-positive immunhistochemical staining.3 Mutation analysis for BRAF (V600) was positive in a sample from the thoracic aorta. An occlusion of the arteria radicularis magna had presumably induced the spinal ischaemia. Septic multiple organ failure was attributed to perforation of the sigmoid colon with ischaemic colitis.
This case demonstrates that ECD, a very rare non-Langerhans-cell histiocytosis characterised by xanthogranulomatous infiltration of tissues,3 can mimic LVV. Both, giant cell arteritis and Takayasu's arteritis can affect various segments of the aorta, including their primary branches. FDG-uptake of large vessels in PET/CT is not specific and can be misleading. However, in most patients with ECD, symmetric lesions of long bones in FDG-PET or bone scintigraphy and specific histological features lead to the diagnosis.3 Vascular manifestation is based on periaortic fibrosis and perivascular xanthogranulomatous infiltrates,2 though diffuse involvement of multiple large vessels is uncommon in ECD. Although inflammatory infiltrates are restricted to the adventitia compared to LVV,2 conventional vessel imaging by CT, MRI and FDG-PET cannot differentiate between these diseases.
Contributors The authors were involved in the clinical (PO, GW and TN) or pathological (IP and BS) and diagnostic management (EL and TW) of the patient as well as writing the manuscript (CW, PO, GW and TN), which was read and approved by all authors.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.