Abstract
Purpose :
IgG4-related disease (IgG4-RD) is a heterogeneous fibroinflammatory condition recognized as a novel clinical entity with IgG4-bearing plasma cell infiltration. Our intention was to investigate the prevalence of positive IgG4-immunostaining in patients with idiopathic orbital inflammatory pseudotumor (IOIP), and to compare the clinical, radiologic and pathologic features among patients associated with IgG4-RD and those without IgG4.
Methods :
A retrospective histopathological review and clinical case series.165 patients with biopsy-proven IOIP were included. Biopsy samples with more than 10 IgG4-positive plasma cells per high-power field and a IgG4+/IgG+ plasma cell ratio above 40% were scored as positive. Histopathologic analysis and serum IgG4, C3 and C4 levels, when available, were also documented.
Results :
IOIP patients had a mean age of 42 years, 52% were male, and 38% of cases were bilateral. The lacrimal gland was the most commonly involved structure, while none of them had conjunctival involvement. Of the 165 patients included, immunohistochemical staining showed 100 cases (60.6%) were IgG4 positive. The latter patients showed a lower female-to-male ratio (0.67:1 vs. 1.6:1, p=0.007), an association with bilateral orbital involvement (p=0.000), relatively elevated serum IgG4 levels (p=0.050), decreased C3 (p=0.020) and C4 (p=0.580) concentrations. The presence of positive IgG4-immunostaining was significantly associated with higher Ki-67.
Conclusions :
More than half of patients with biopsy-proven IOIP classified criteria for IgG4-RD. Furthermore, the presence of different clinical, radiologic and histological features in IOIP suggests that IgG4-related IOIP may have a different pathogenesis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.