Extending the spectrum of a chameleon: IgG4-related disease appearing as interstitial nephritis and mimicking anti-neutrophil cytoplasmic antibodyassociated vasculitis.

The article discusses the case of a 54 year old female patient of Caucasian descent presented with a past medical history including Hashimoto thyroiditis diagnosed in 2006. Further investigations were initiated including ENT, ophthamological and neurological assessments due to a suspected diagnosis of granulomatosis with polyangiitis. The case is the first description of an IgG4-related tubulointerstitiial nephritis with concomitant positivity of cytoplasmic ANCA and PR3.