title: Medical mirroring: granulomatosis with polyangiitis (formerly Wegener's) mimicking immunoglobulin-G4 related disease.
abstract: Granulomatosis with polyangiitis (GPA; formerly Wegener's) can present with clinical and histopathological features similar to those of immunoglobulin-G4 related disease (IgG4-RD), a recently described fibro-inflammatory condition. The ability of these two distinct entities to mimic each other closely creates significant pitfalls in diagnosis. We present a unique case in which GPA presented as a peri-aortic fibrotic mass in the retroperitoneum. The patient's other clinical features also overlapped with classic IgG4-RD disease manifestations, but the histopathology in two organs and the serological data confirmed the diagnosis of GPA. Rigorous histopathological review remains the gold standard for the diagnosis of GPA and the distinction of this entity from IgG4-RD and other mimickers.
authors.affiliation: Albany Stratton Veterans Affairs Medical Center (VAMC), Albany, New York, USA.|Albany Medical College, Albany, New York, USA.
authors.forename: Prashant
authors.initials: P
authors.lastname: Kaushik
authors.affiliation: Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA.|Clinical Rheumatology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Stone
authors.affiliation: Albany Medical College, Albany, New York, USA.
authors.forename: James T
authors.initials: JT
authors.lastname: Anderson
authors.affiliation: Albany Medical College, Albany, New York, USA.
authors.forename: Shaifali
authors.initials: S
authors.lastname: Dugar
authors.affiliation: Albany Stratton Veterans Affairs Medical Center (VAMC), Albany, New York, USA.|Albany Medical College, Albany, New York, USA.
authors.forename: Roy
authors.initials: R
authors.lastname: Mathew
authors.affiliation: Albany Stratton Veterans Affairs Medical Center (VAMC), Albany, New York, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Nikolic
authors.affiliation: Albany Stratton Veterans Affairs Medical Center (VAMC), Albany, New York, USA.
authors.forename: Raina
authors.initials: R
authors.lastname: Patel
mesh_terms: D061605:Administration, Intravenous; D000284:Administration, Oral; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis*; D001706:Biopsy; D003937:Diagnosis, Differential; D004359:Drug Therapy, Combination; D005938:Glucocorticoids / Q000008:administration & dosage; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D011241:Prednisone / Q000008:administration & dosage; D020551:Pulse Therapy, Drug; D012074:Remission Induction; D012185:Retroperitoneal Fibrosis / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D000069283:Rituximab / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D005938:Glucocorticoids; D007074:Immunoglobulin G; D000069283:Rituximab; D011241:Prednisone; D008775:Methylprednisolone
keywords: IgG4-related disease (IgG4-RD); diagnostic challenge; granulomatosis with polyangiitis (GPA)