IgG4-Related Lung Disease: Retrospective Review of 9 Cases

Abstract

SESSION TITLE: Pulmonary Manifestation of Systemic Disease SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 26, 2016 at 01:30 PM - 02:30 PM PURPOSE: IgG4-related disease is a corticosteroid-responsive systemic fibroinflammatory disease that affects various organs. Although pancreatic involvement is the most common presentation, pulmonary manifestation, known as IgG4-related lung disease (IgG4-RLD) has been increasingly recognized. While many reports are from Asian populations, we aimed to clarify the clinical and pathologic aspects of IgG4-RLD in non-Asian populations. METHODS: A retrospective review was conducted of cases with biopsy-proven IgG4-RLD encountered from January 1994 till February 2016 at an academic medical center. IgG4-RLD was defined as meeting at least 2 out of 3 characteristic histopathological features (IgG4-positive lymphoplasmacytic infiltration, fibrosis, and obliterative phlebitis) with IgG4+ cell counts of more than 50 per high power field (HPF) in either surgical or nonsurgical specimens and IgG4+: IgG+ ratio of greater than 0.4 in combination with compatible clinicoradiologic features. We also included cases manifesting at least one histopathologic feature, IgG4+ cell counts per HPF of more than 50 in a surgical specimen or more than 20 in a nonsurgical specimen, with IgG4+: IgG ratio of greater than 0.4, if either elevated serum IgG4 level or initial favorable corticosteroid responsiveness (or complete surgical resection) was seen along with compatible clinicoradiologic features. RESULTS: A total of 9 patients with IgG4-RLD were identified, of which 8 were male and all were Caucasians. The median age at diagnosis was 64 years (interquartile range [IQR], 59-70). Serum IgG4 measurement was available in 8 patients, and the median peak serum IgG4 level was 234 mg/dL (IQR, 93-479). Five patients had respiratory symptoms on presentation, of which cough (N=4) and dyspnea (N=4) were most common, followed by nasal congestion (N=3). The main radiographic abnormality that led to biopsy was seen in the parenchyma (mass or nodule) in 7 patients, the central airway (stenosis) in 1 patient, and the pleura (pleural thickening and effusion) in 1 patient. The secondary radiographic abnormality was seen in 5 patients; 4 had mediastinal and/or hilar lymphadenopathy, and 1 had bronchial stenosis. The median count of IgG4+ cells was 65 (IQR, 49-117) per HPF, and the median IgG4+:IgG+ ratio was 0.56 (IQR, 0.47-0.74). No medical treatment was immediately necessary in 4 patients who underwent complete surgical resection of the pulmonary lesion. Among those patients; however, 3 had a recurrence of IgG4-RLD and received either corticosteroids or steroid-sparing agents during the clinical follow-up. The remaining 5 patients received corticosteroids immediately after the diagnosis of IgG4-RLD. All 5 patients subsequently developed either recurrence of IgG4-RLD or experienced the re-emergence of IgG4-related disease in the extra-pulmonary organs. CONCLUSIONS: IgG4-RLD is the pulmonary manifestation of IgG4-related disease, which commonly affects middle-aged or elderly men, with a high propensity for recurrence. Majority of patients present with mass or nodule with associated lymphadenopathy. CLINICAL IMPLICATIONS: IgG4-RLD mimics malignancy or other infectious or inflammatory conditions in its presentation. DISCLOSURE: The following authors have nothing to disclose: Reina Suzuki, Eunhee Yi, Jay Ryu, Hiroshi Sekiguchi No Product/Research Disclosure Information