Background IgG4-related disease (IgG4-RD) is a rare fibro-inflammatory condition characterized by expansive lesions, serum IgG4 elevation in the majority of cases, and a prompt response to glucocorticoids (GCs) . The diagnosis of IgG4-RD might be challenging because clinical manifestations are largely non-specific and overlap with other inflammatory and neoplastic conditions. The current gold standard for the diagnosis of IgG4-RD is the identification of characteristic histological features that are strikingly similar across the full range of organs affected. These features include a dense tissue fibrosis with a storiform pattern, a diffuse lymphoplasmacytic infiltrate with abundant IgG4-positive plasma cells, mild to moderate eosinophilia, and obliterative phlebitis . GCs represent the first-line treatment for induction of remission, and typically lead to dramatic clinical responses in the majority of cases with both pancreatic and extra-pancreatic disease .
Objectives To describe the clinical features, treatment response and follow-up of a large cohort of Italian patients with IgG4-related disease (IgG4-RD) referred to a single tertiary care centre.
Methods Clinical, laboratory, histological and imaging features were retrospectively reviewed. IgG4-RD was classified as “definite” or “possible” according to international consensus guidelines and comprehensive diagnostic criteria for IgG4-RD. Disease activity was assessed by means of the IgG4-RD Responder Index (IgG4-RD RI).
Results Forty-one patients (14 females, 27 males) were included in this study, 20 with “definite” IgG4-RD, and 21 with “possible” IgG4-RD. The mean age at disease onset was 62 years. The mean follow-up was 34 months (range 6-83 months). A history of atopy was present in 30% of patients. Pancreas, retroperitoneum, and major salivary glands were the most frequently involved organs. Clinical characteristics of the patients' cohort at IgG4-RD onset are summerized in table 1. Serum IgG4 were elevated in 68% of cases. Thirty-six patients were initially treated with glucocorticoids for inducing remission. IgG4-RD RI decreased from a mean of 7.8 at baseline to 2.9 after 1 month of therapy. Relapse occurred in 19/36 patients (53%) and required additional immunosuppressive drugs to maintain long-term remission. No further relapses were observed. A single case of orbital pseudotumor did not respond to medical therapy and underwent surgical debulking.
Conclusions IgG4-RD is an elusive inflammatory disease to be considered in the differential diagnosis of isolated or multiple tumefactive lesions. Long-term disease control can be achieved with corticosteroids and immunosuppressive drugs in the majority of cases.
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Disclosure of Interest None declared