Erdheim-Chester disease: a case report

Erdheim-Chester disease (ECD) is a rare histiocytosis, histologically characterized by xanthogranulomatous inflammation. It may affect the bones, heart, lung, liver, kidneys, retroperitoneum, brain, and, rarely, the orbit. In the majority of patients, orbital infiltration is bilateral.

A 61-year-old man presented with bilateral exophthalmos and progressive loss of visual function caused by chorioretinal folds and papillary swelling due to retrobulbar pseudotumor. The computed tomogram of the abdomen showed retroperitoneal thickening, leading to the interpretation of multifocal fibrosclerosis. This was further substantiated by an orbital biopsy revealing chronic fibrosing inflammation. Retrobulbar radiotherapy (20 Gy) and long-term systemic corticosteroid treatment followed. Although the retroperitoneal involvement decreased, no significant effect on orbital involvement was achieved. A second review of the orbital biopsy revealed foamy cell infiltration and the presence of a sclerotic process. Immunohistochemical examination demonstrated positive CD 68 stains, whereas S-100 and CD 1a were negative, thus confirming ECD. The histologic finding was comparable to a biopsy of the retroperitoneum. Endonasal decompression was performed but visual acuity (VA) decreased to 20/250 in the right eye and on finger counting in the left eye. The patient continues to be under therapy with prednisolone 20 mg/day and methotrexate 25 mg/week.

The clinical orbital manifestation of ECD occurs in two different forms: one presenting as a mild impairment of visual function, while the second, clinical form, observed in our patient, is characterized by a progressive loss of VA despite therapeutic efforts such as immunosuppressive systemic therapy, radiation, and surgery. The described case illustrates that clinical findings in multifocal fibrosclerosis overlap with those observed in ECD.