Clinical pearls on Erdheim-Chester disease: ➕"Hairy Kidneys" on CT ➕"Coated" aorta or periaortitis ➕PET scan can confirm diagnosis - affects distal long bones ➕Refer to Oncology for treatment - it's a histiocytic neoplasm!🤓 @RheumNow #ACR21 #MedTwitter https://t.co/MsIqk1rWvE