A case of adult-onset Still’s disease with eyelid xanthogranuloma mimicking Erdheim-Chester disease

We report an exceptionally rare but interesting case of adult-onset Still disease (AOSD) accompanied by large xanthogranuloma of the eyelid in a patient who had symptoms reminiscent of Erdheim–Chester disease (ECD). The symptoms of AOSD and ECD overlap; therefore, we believe it is important to remind clinicians that when xanthogranuloma occurs in a patient with AOSD, the possibility of ECD should be considered.