Presentation
Patient was referred for specialized physician assessment with general malaise and deterioration in renal function. eGFR on presentation was 19, creatinine 217. Systolic BP was 220 mmHg on a background of hypertension, resistant to medical therapy.
Patient Data
- diffuse, irregular mural thickening (HU 56) of the thoracic and abdominal aorta causes high grade stenosis of the renal arteries bilaterally
- left subclavian artery mural thickening
- right atrial posterior mural lesion/ mass with small volume pericardial effusion
- bilateral perinephric fat stranding
Sclerotic bony infiltrates within the lower limb long bone metaphyses and diaphyses.
PET CT demonstrating PET avidity within the perivascular soft tissue thickening and most marked within the right atrial mass like lesion.
4 chamber and atrial SAX steady state free precession sequences and coronal T2 sequence confirming right atrial nodular mural thickening giving the appearance of a pseudotumor and diffuse aortic mural thickening with small pericardial effusion.
After the physician review, A CT angiogram was performed to assess the renal arteries and to exclude PE. The CT showed extensive irregular thickening of the aortic wall, present for 2 years with a concomitant right atrial mass. Associated high-grade stenosis of both renal arteries was well demonstrated, explaining the patient's renal presentation. The patient was referred for PET to investigate the possibility of giant cell arteritis. The lesions were shown to be PET avid, with additional lesions identified in the region of the foramen magnum and lower limbs.
Review of prior imaging for lower limb joint replacement surgery confirmed the presence of sclerotic bone infiltrates in typical locations in the regions of PET avidity, confirming the diagnosis of Erdheim Chester disease.
Subsequent bone marrow biopsy yielded the following: 'Features are those of marrow involvement with a sclerotic xanthogranulomatous reaction compatible with Erdheim-Chester disease. Radiological correlation is necessary.'
Case Discussion
Erdheim-Chester disease is a rare, non-Langerhans form of systemic histiocytosis, occurring in middle age to older patients, which causes infiltrates in the bones and soft tissues by foamy histiocytes. The disease has characteristic radiological findings and the diagnosis is frequently reliant on imaging. Histological examination alone, although important, is often not sufficient to confirm the diagnosis.
Bilateral, symmetrical osteosclerosis of the long bones involves the metaphyses and diaphyses, sparing the epiphyses and is more common in the lower limbs. Bone scintigraphy is an excellent modality to demonstrate these changes. These changes are pathognomonic and confirm the diagnosis.
Retroperitoneal soft tissue infiltrates affecting the ureters, kidneys and renal arteries is a frequent feature, and patients often present with renal impairment.
Cardiovascular manifestations are present in more than half of patients, with aortic infiltration and atrial pseudotumor being the most common forms.
The diagnosis is often challenging, with lengthy delays, and recognition of the vascular and skeletal findings is key.
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