Purpose
IgG4-related disease (IgG4-RD) is an emerging entity characterized histopathologically by a lymphoplasmacytic infiltrate with increased numbers of IgG4-positive plasma cells (IgG4+ PC). In the last decade, IgG4-RD has been described in multiple organs, including the lung and orbit. Several case reports have appeared in recent pulmonary literature demonstrating evidence of concurrent sarcoidosis and IgG4-RD. The purpose of this study is to determine the strength of association between IgG4-RD and clinically documented and orbital biopsy-confirmed sarcoidosis.
Methods
The databases of orbital biopsies performed at the New York Eye and Ear Infirmary (NYEEI) and the SUNY Downstate Medical Center between 1990 and 2013 were searched for "sarcoidosis" and/or "granulomatous inflammation" and/or "granuloma." Patients with orbital biopsies suggestive of sarcoidosis (i.e. non-caseating granulomas), who also had clinical, serologic, and/or radiographic evidence of systemic sarcoidosis, were included. Paraffin-embedded tissue blocks were sectioned and immunostained with IgG4 and IgG antibodies. Histopathology and the degree of IgG4+ PC infiltration were evaluated by 1 ophthalmic pathologist. This study is NYEEI Institutional Review Board approved.
Results
Nine patients with orbital biopsies consistent with sarcoidosis and clinical diagnosis of sarcoidosis were identified. Histopathologic findings included discrete non-necrotizing granulomas in 9/9 (100%) patients, mild focal non-storiform fibrosis in 5/9 (56%), moderate focal non-storiform fibrosis in 4/9 (44%), obliterative phlebitis in 1/9 (11%), and mild to moderate lymphoplasmacytic infiltrate in 8/9 (89%). One patient had moderate to severe lymphoplasmacytic infiltrate with elevated IgG4+ PC count >50 per high power field (HPF), IgG4:IgG ratio >90%, elevated total serum IgG and IgG1, 2, and 3 subsets, but normal IgG4. The remaining patients had an average IgG4+ PC count of 5.3 per HPF (range 0-21), and IgG4:IgG ratio of 6.6% (range 0-22%).
Conclusions
These results confirm prior data indicating an infrequent association of sarcoidosis with IgG4-RD. These observations are limited by the small sample size, lack of reliable diagnostic criteria for orbital IgG4-RD, and lack of consensus on IgG+ and IgG4+ PC quantification algorithms. Further research is needed to elucidate whether elevated tissue and serum levels of IgG4 in patients with sarcoidosis have clinical significance.
Keywords: 631 orbit •
639 pathology techniques •
554 immunohistochemistry