L45. Aortitis, retroperitoneal fibrosis, and IgG4-related disease

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

Practical approach to vasculitides in adults: an overview of clinical conditions that can mimic vasculitides closely

Primary systemic vasculitides are rare diseases affecting blood vessel walls. The type and patterns of distribution of the organs affected usually reflect the size of the vessels predominantly involved, and the patterns of clinical manifestations are generally useful to reach a specific diagnosis. However, presenting symptoms may lack adequate specificity for a prompt diagnosis, leading to a diagnostic (and therapeutic) delay, often causing irreversible damage to the affected organs. Due to their rarity and variable clinical presentation, the diagnosis of primary vasculitides could be challenging for physicians. Vasculitis mimickers, i.e. the clinical conditions that could be likely mistaken for vasculitides, need to be carefully ruled out, especially before starting the immunosuppressive therapy. We present here a practical approach to the diagnosis of primary systemic vasculitides involving large, medium and small size vessels, and reviewed most of the conditions that could mimic primary systemic vasculitides.

Clinical features and prognostic factors of ten patients with renal failure caused by IgG4-related retroperitoneal fibrosis

IgG4-related retroperitoneal fibrosis (IgG4-RPF) is a newly recognized entity which often mimics cancer. We aimed to investigate the clinical features and the causes of renal failure, as well as to explore the factors affecting the prognosis of renal function by analysis of the clinical data of patients with IgG4-RPF. We reviewed clinical features of 10 patients with renal failure caused by IgG4-RPF, which was confirmed by pathology review and clinic-pathologic correlations. All patients were male, and the mean age at onset was 64.2 ± 10.0 years. Five patients were revealed with acute renal failure (ARF), while the other five ones with ARF on chronic kidney disease (CKD) (A on C) at diagnosis. Initial favorable responses obtained in 90% of the patients who underwent steroid therapy. The serum creatinine (SCr) level returned to normal in six patients including five with ARF and one with A on C, while those of the rest four patients with A on C restored to baseline levels (GFR remained below 60 ml/min/1.73 m² however) after therapy. These four unrecovered patients had a history of CKD, a longer period of persistently elevated SCr, a thinner total renal parenchyma thickness, and continuous elevated serum IgG4 levels after steroid therapy, compared with those recovered patients (P < 0.05). We concluded that recovery and long-term prognosis of the disease were primarily associated with timely diagnosis and proper treatment.

Retroperitoneal fibrosis due to B-cell non-Hodgkin lymphoma: Responding to rituximab!

Retroperitoneal fibrosis is a rare disease manifesting as chronic soft tissue fibrosis in the retroperitoneum, with potential anatomic and/or functional compromise of adjacent organs. It can be primary (idiopathic) or secondary to other conditions such as cancers, autoimmune disorders, or drugs. We report herein a 66-year-old patient with symptomatic retroperitoneal fibrosis leading to bilateral hydronephrosis and renal failure, in whom, after a complex diagnostic work-up and protracted clinical course, a B-cell non-Hodgkin lymphoma in the retroperitoneal space and several vertebral bodies was identified. The patient was treated with radiation therapy and weekly rituximab infusions, with resolution of hydronephrosis and lower back pain. We include a thorough literature review on etiopathogenesis, diagnosis, therapy, and prognosis of retroperitoneal fibrosis. A meticulous search for malignancy is necessary in this rare condition that, if positive, may have significant therapeutic and prognostic implications.