CASE 13417 Published on 12.09.2016

Erdheim-Chester disease


Musculoskeletal system

Case Type

Clinical Cases


Leenknegt Benjamin, Dutoit Julie, Verstraete Koenraad

Department of Radiology,
Ghent University Hospital

73 years, male

Area of Interest Neuroradiology brain, Musculoskeletal bone, Bones, Extremities, Arteries / Aorta, Thoracic wall, Respiratory system, Adrenals, Stomach (incl. Oesophagus), Kidney ; Imaging Technique PET, CT
Clinical History
A 73-year-old man was referred to the internal medicine department. His complaints were lifelessness and physical deconditioning since one and a half year. Laboratory results showed microcytic anaemia and raised inflammatory markers. A gastroscopy, colonoscopy and bone marrow aspiration could not reveal any suspicious findings. 18FDG-PET/CT imaging was performed.
Imaging Findings
CT imaging of the legs shows medullar osteosclerosis with cortical thickening, affecting the diaphysis and metaphysis. High FDG uptake in the corresponding areas on 18FDG-PET imaging (1a, b). CT imaging of thorax and abdomen shows soft tissue infiltration around the aorta (2a-e), expanding into the left and right paravertebral space (2a-c). Note the retrosternal (2a) and pleural soft tissue infiltration (2b). The adrenal glands are swollen with soft tissue infiltration of the adjacent fat. Increased FDG tracer uptake in the adrenal glands, around the aorta and in the stomach (2d). Soft tissue infiltration in the left and right perirenal and posterior pararenal space (‘hairy kidney’ sign), expanding into the renal sinuses (2e). A left-sided hypermetabolic spot anterior to the middle cerebral artery and a high FDG tracer uptake in the small bones of the feet on 18FDG-PET imaging, with no corresponding lesions on CT imaging (3a, b).
Erdheim-Chester Disease (ECD) is a rare multisystemic disease of unknown aetiology [1, 2]. It is characterized by a typical pattern of osseous infiltration and a varying degree of extraskeletal involvement [3, 4]. Most frequent symptoms are bone pain, diabetes insipidus, exophthalmos, renovascular hypertension or neurological manifestations [4-6].

Osseous infiltration generally consists of a symmetric bilateral osteosclerosis in the metaphysis and diaphysis of the long bones [2, 3, 5]. Other radiographic features are osteolysis, cortical thickening, narrowing of the medullar cavity, a blurred corticomedullary margin, a metaphyseal radiolucent band and signs of periostitis. On MR imaging, osteosclerosis is hypointense on T1-weighted images and hyperintense on T2-weighted images; enhancing after gadolinium injection [3].
Bilateral soft tissue infiltration of the perirenal and posterior pararenal space is called the ‘hairy kidney’ sign. This sign consists of a homogeneous band with spiculated contours, hypoattenuating on CT imaging and isointense to muscle on T1 and T2 weighted MR imaging [2, 4]. Infiltration can expand into the adrenal fossa [4, 5]. Diffuse circumferential involvement of the aorta is called the ‘coated aorta’, hypo-attenuating on CT imaging and isointense to muscle on T1- and T2-weighted images [2, 4]. Cardiac involvement manifests as pericardiac soft tissue thickening, pericardiac effusion or a myocardial pseudo-tumorous mass. On high resolution CT imaging smooth septal thickening, centrilobular nodules or pleural thickening can be seen [2, 4, 5]. Retro-orbital soft tissue involvement is usually intraconal, bilateral and lacks signal intensity on T1 and T2 weighted MR imaging. Hypothalamic-pituitary axis involvement appears on T1 weighted MR imaging as a nodular mass in the pituitary stalk or an absence of signal in the posterior pituitary [5]. Neurological involvement can manifest as nodules or mass lesions in the brain, the meninges or the spinal cord with an increased signal intensity on T2 weighted MR imaging and prolonged enhancement after gadolinium injection on T1 weighted MR imaging [6, 7].

99mTc bone scintigraphy and 18FDG-PET/CT imaging have the advantage of performing a whole-body examination [3, 8]. 99mTc bone scintigraphy will demonstrate an increased tracer uptake in all bony lesions and can detect radiographically silent bone involvement [3]. 18FDG-PET/CT imaging demonstrates a high FDG uptake in all metabolically active lesions [8].

Diagnosis of ECD is suspected on imaging findings and confirmed by histological analysis of a biopsy. Globally, prognosis is poor and therapeutic options are scarce. Medical treatment includes corticosteroids, bisphosphonates, cytotoxic agents and immunosuppressive drugs [2, 5]. Surgical intervention is indicated when a mass compresses the brainstem or the spinal cord [6].
Differential Diagnosis List
Diagnosis of Erdheim-Chester Disease was confirmed on a bone biopsy.
Langerhans cell histiocytosis
Rosai-Dorfman disease
Paget’s disease
Idiopathic retroperitoneal fibrosis [9]
Final Diagnosis
Diagnosis of Erdheim-Chester Disease was confirmed on a bone biopsy.
Case information
DOI: 10.1594/EURORAD/CASE.13417
ISSN: 1563-4086