Radiological assessment of extremity bone involvement in Erdheim-Chester disease: a systematic review of case reports

To describe the clinical presentations and radiological manifestations of Erdheim-Chester disease (ECD) in the extremities, with particular emphasis on radiologic findings, as radiographs are typically the initial imaging modality used in clinical practice.

Following the PRISMA guidelines, a comprehensive systematic search was performed across Scopus, PubMed, Web of Science, and Embase databases, covering case reports from inception until August 1, 2024. Included were studies with pathologically confirmed ECD (CD68 positive and CD1a negative) that were evaluated with at least one imaging modality and provided detailed descriptions of radiological findings.

Out of 401 identified articles, 20 articles comprising 20 histologically confirmed cases of ECD met the inclusion criteria following screening and full-text review. Pathological reports were assessed for the presence of lipid-laden cells and Touton giant cells, which were identified in 84.2% and 75% of cases, respectively. Upper extremities were affected in 65% of cases and lower extremities in all cases. Symmetric involvement was observed in 84.6% of upper extremity cases and 84.2% of lower extremity cases. Radiological findings were categorized as pure sclerosis (53.3%) and cortical thickening (42.8%) identified as the most common findings. Clinical manifestations were assessed, with pain and swelling in the extremities being the most common symptoms, occurring in 70% of cases.

The hallmark of ECD is bilateral, symmetric diaphyseal and/or metaphyseal osteosclerosis in the long tubular bones of the lower extremities. Epiphyseal sparing is observed in more than half of the patients.