Erdheim-Chester disease as complex clinical presentation and diagnosis: A case report and concise review of literature.

RATIONALE: Erdheim-Chester disease (ECD) is a rare multisystemic disease characterized by the infiltration of multiple organs by foamy CD68 + CD1a-histiocytes. The genetic background consists of gain-of-function somatic mutations in the mitogen-activated protein kinase pathway. The purpose of the present paper is to make a contribution to the scientific literature on ECD by reporting our experience with a complex clinical case report, along with a concise review of the literature. We discussed the unusual clinical presentation, the complex diagnostic process and the comparison with other published cases.

PATIENT CONCERNS: A 70-year-old man presented with arthralgia due to multiple bone areas of sclerosis, first diagnosed with metastases of a prostatic neoplasm. Sequential thorax-abdomen, femoral and homer contrast-enhanced computed tomography (CT) showed pericardial effusion, pulmonary fibrosis, and perirenal fibrous tissue as "hairy kidneys." He underwent. Three bone biopsies were unsuccessful to reach diagnosis.

DIAGNOSES: A xanthelasma biopsy showed histopathological signs compatible with ECD; genetic analysis showed the mutation BRAFV600E.

INTERVENTIONS: The patient underwent targeted therapy with vemurafenib (BRAF-inhibitor), discontinued 2 weeks later due to the onset of a diffuse erythematous papular rash on the trunk and limbs.

OUTCOMES: At the 1-year follow-up, there was only progression of chronic kidney disease (CKD).

LESSONS: The present case report describes how ECD diagnosis could represent a challenge for clinicians, owing to its heterogeneous clinical presentation. Early diagnosis followed by prompt therapy is essential for modifying the natural history of the disease.