LAUSR

Purpose Immunoglobulin G4-related disease is a systemic fibroinflammatory disease of unknown etiology. Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) can manifest in multiple ways, but lacrimal sac involvement is rare. We present the first case in Chinese population of lacrimal sac IgG4-ROD. Observations Lacrimal sac IgG4-ROD is rare, and only 9 cases were reported in literature. Despite reported cases in Asian population, mainly in Japan, there was none from the Chinese population or South Asia. Our index case is a 67-year-old Chinese male, who presented with a left insidious nasolacrimal duct swelling mimicking dacryocystocele. Lacrimal sac IgG4-ROD was diagnosed with radiological, serological, pathological and immunohistochemical evidence. The under-reporting of this disease entity may suggest a benign course of such. Conclusions and importance This is the first reported case of biopsy proven lacrimal sac definite IgG4-ROD in Chinese patient on English literature. With the limited cases reported in literature, the pathology of Immunoglobulin G4 immune process in lacrimal sac demands further investigation.