Microscopic Hematuria as a Rare Presentation of Erdheim-Chester Disease

Erdheim-Chester disease (ECD) is a rare disease radiologically characterized by bilateral symmetric multifocal long bone osteosclerotic lesions, perinephric soft tissue rinds and smooth pleural thickening. Biopsy typically reveals foamy histiocyte sheets. With bone pain as the most common presenting symptom, we report an atypical case of a 65-year-old male presenting solely with microscopic hematuria. Contrast enhanced CT demonstrated bilateral perinephric soft-tissue rinds and a left perinephric mass, which post-biopsy, was negative for both lymphoma and renal neoplasm, however, revealed foamy histiocytes. A skeletal survey was performed demonstrating bilateral symmetric long bone lesions with increased metabolic activity on PET CT. The radiologic and pathological findings were congruent and suggestive of ECD. Given his rather benign presentation, it was elected to conservatively manage and radiologically monitor his condition with annual CTs and skeletal surveys with no significant medical presentation in 4 years of follow-up.