Case of the Month January 2015, page 5

Answer 4:

CASE ANSWER: Erdheim-Chester Disease

Differential Diagnosis:

1. Retroperitoneal lymphoma – associated with lymphadenopathy; rarely results in obstruction
2. Retroperitoneal metastasis with desmoplastic reaction –associated with lymphadenopathy
3. Sequelae of retroperitoneal hemorrhage – commonly asymmetric; often involves the iliopsoas.
4. Retroperitoneal fibrosis – primary fibrosis typically extends from medial to lateral, surrounding the vessels.
5. Takayasu’s Arteritis – typically demonstrates transmural arterial wall involvement.
6. Langerhans Cell Histiocytosis – May demonstrate similar osseous and thoracic findings.  Less commonly involves the abdomen/pelvis.

SUMMARY:

Nearly circumferential fibrosis about the pararenal fascia (the “hairy-kidney” sign), resulting in ureteral obstruction at the level of the renal hilum and progressive renal failure.  A lack of significant lymphadenopathy and a sparing of the peri-aortic space help point towards a diagnosis of retroperitoneal Erdheim-Chester disease.

DISCUSSION:

Erdheim-Chester disease is an uncommon form of histiocytosis (specifically, non-Langerhans’ cell histiocytosis) that presents in middle age.  Findings are predominantly thoracic or musculoskeletal in contrast to this case.  Morbidity is most commonly related to the development of fibrosis and, as such, symptoms and presentations can be variable.  Abdominal forms can be associated with renal or liver failure.  Treatment typically involves some combination of surgical debulking, corticosteroids, radiation, or chemotherapy.

RADIOLOGIC FINDINGS:

 Thoracic – Diffuse thickening of interlobular septae; smooth pleural thickening and effusion; pericardial thickening and effusion.  Pericardial involvement bears a poor prognosis.
 Abdominal – Retroperitoneal involvement is present in two-thirds of cases.
 Head/Neck – Fibrosis may symmetrically affect the orbits or encase the pituitary stalk, resulting in diabetes insipidus.
 Vascular – Fibrosis may sometimes circumferentially encase the aorta.
 Musculoskeletal – Cortical sclerosis of the long bones with epiphyseal sparing; seen in almost all patients (96%) with Erdheim-Chester Disease.

1. Chung, JH.  Erdheim-Chester Disease.  StatDx.com
2. Dion E, et al.  Imaging of thoracoabdominal involvement in Erdheim-Chester Disease.  Am J Roentgenol. 183(5): 1253-60, 2004.
3. Antunes C, et al.  Thoracic, Abdominal, and Musculoskeletal Involvement in Erdheim-Chester Disease: CT, MR, and PET Imaging Findings.  Insights Imaging.  5(4): 473-482, Aug 2014.
4. Mazor RD, et al. Erdheim-Chester Disease: a comprehensive review of the literature. Orphanet J Rare Dis. 8: 137.  Sept 2013.


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