Erdheim-Chester disease

Case contributed by Dr Michael P Hartung

Presentation

Abdominal discomfort.

Patient Data

Age: 75 years
Gender: Female
CT

Thickening and enhancement of the right atrial wall (partially seen). 

Soft tissue thickening of the descending thoracic and abdominal aorta. 

Near occlusion/occlusion of the SMA with circumferential soft tissue thickening. 

Left perinephric soft tissue thickening with infiltrative, enhancing tissue in the renal hilum, resulting in mild/moderate hydronephrosis. 

Similar infiltrative soft tissue in the right renal hilum without obstruction. 

X-ray

Left tibia radiograph

No sclerotic lesions are detectable on radiograph. 

Nuclear medicine

Whole body bone scan

Whole body bone scan shows uptake in the left > right tibia. 

PET/CT whole body

Abnormal FDG uptake in the following locations:

  • Right atrium (rind of thickening/uptake)
  • Descending thoracic aorta (note thickening on CT images)
  • Renal hilar activity better appreciated on CT as it overlaps with normal excretion of radiotracer
  • Left greater than right tibial shaft (medullary cavity)
CT

CT-guided biopsy

Planning images from CT-guided left tibial biopsy shows faint areas of sclerosis within the medullary cavity corresponding to increased PET/CT and bone scan uptake. 

Left tibial biopsy pathology report:

  • Bone marrow with fibrosis, remodeling and focal xanthomatous-appearing histolytic infiltrate
  • Immunohistochemical stains + for CD 68, - for CD1a
  • BRAF600 mutation negative

Case Discussion

Biopsy-proven case of Erdheim-Chester disease (ECD).

ECD is a non-Langerhan-cell histiocytosis of unclear etiology. It is characterized by abnormal proinflammatory cytokine response resulting in systemic proliferation and infiltration of histiocytes, and can involve any organ system. Bone pain most common presentation. Diagnosis made on the basis of imaging features and the presence of foamy histiocytes (CD68+ and CD1a-).

The major presenting feature on this case was the perirenal and renal hilar soft tissue infiltration. The differential for that finding alone includes:

  • Erdheim-Chester disease ("hairy kidney")
  • lymphoma/lymphoproliferative
  • igG4-related sclerosing disease
  • retroperiteonal fibrosis
  • plasmacytoma
  • extramedullary hematopoesis
  • amyloidosis

However, taking into account the additional findings of right atrial soft tissue thickening (only partially seen on the first few images, but a common feature of ECD), coating of the aorta/SMA, and absence of findings typical of the other diagnoses (e.g. no adenopathy for lymphoma, no auto-immune pancreatitis for igG4, RPF usually starts at the aortic bifurcation and ascends, no history of multiple myeloma, no hepatosplenomegaly for EMH or amyloidosis), ECD is the leading diagnosis. 

After reading the CT, it would be reasonable to recommend the following:

  • hematology or rheumatology consultation
  • check igG4 levels (even though less likely, if they are elevated, this patient can be treated with steroids and avoid risk of biopsy)
  • extremity long bone radiographs to look for medullary sclerotic lesions typical of ECD
  • depending on those results, PET/CT and bone scan can also play a role in evaluating the extent of disease and identifying the safest biopsy target. In this case, a first attempt was made at CT-guided biopsy of the left perirenal soft tissue thickening (not shown), but was unsuccessful. The bone scan was essential for identifying a target in the left tibia, which was occult on radiographs
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Case information

rID: 70575
Published: 27th Aug 2019
Last edited: 27th Aug 2019
System: Urogenital
Inclusion in quiz mode: Included

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