Erdheim-Chester disease (ECD) is a rare disease that includes sclerosis in the upper and lower extremities and extraskeletal involvement. No standard therapy exists, but interferon-α has helped some patients. The prognosis for patients with this condition is poor.
ECD is characterized by a symmetrical sclerosis at the diametaphyseal portions of the upper and lower extremities with additional extraskeletal involvement1 including the kidney and retroperitoneum, lung, pericardium, skin, orbit, and brain. Infiltration of the pituitary stalk may lead to diabetes insipidus2. Skeletal involvement is characteristically bilateral and symmetric, with a characteristic bone scan finding of increased uptake in metaphyses and diaphyses of the long bones, usually sparing epiphyses.
A 56-year-old man with a history of central diabetes insipidus presented with an 8-month history of right-side leg pain. On clinical examination, exophthalmos was noted. The plain radiographs of his extremities (Figure 1) showed coarsened trabecular pattern and sclerosis mainly in the metaphyses. Delayed images in a whole-body bone scan (Figure 2) showed intense increased uptake in a bilateral symmetric distribution involving the metadiaphyseal regions of the tibias and femurs. Diagnosis of ECD was based on the results of plain radiographs and a whole-body bone scan.
Within the distal femur and proximal tibia is a diffuse symmetric diametaphyseal process showing mixed sclerosis (arrows) and slight lucency.
Delayed image in a whole-body bone scan shows intense increased uptake in a bilateral symmetric distribution involving the metadiaphyseal regions of the tibias and femur (arrows). To a lesser extent, similar findings are noted in the forearms.
Our patient was also found to have pulmonary cystic disease, 1-cm soft tissue surrounding both kidneys and the mesenteric vessels, a splenomegaly (Figure 3), and bilateral symmetrical enhancing soft tissue mass within the superior extraconal aspect of both orbits (Figure 4). The diagnosis of ECD was confirmed histologically by a kidney biopsy. It showed dendritic cells rich in a perirenal fibrotic process with lipid-laden histiocytes and Touton-type giant cells, which were positive for CD68 and negative for S-100, consistent with a diagnosis of ECD.
Axial image of a contrast-enhanced computed tomography abdomen scan shows 1-cm soft tissue surrounding both kidneys (white arrows). A soft tissue mass surrounds the mesenteric blood vessels (black arrow).
Sagittal T1-weighted image of the brain shows a soft tissue mass in the superior extraconal aspect of the orbit (arrow). This is seen bilaterally.
The prognosis of patients with ECD is poor. The survival of patients at 3 years is about 59%. The causes of mortality are often from respiratory distress, cardiac failure, or pulmonary fibrosis2.
There is no standard therapy for this disorder, although responses to interferon-α have been reported in some patients. Bisphosphonates and steroid have shown some positive effect for bony pain2. Our patient has now been treated with interferon-α 2b for 1.5 years. On this treatment, his leg pain has mostly disappeared, with improving exophthalmos.
REFERENCES
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