IgG4 related sclerosing sialadenitis- a retrospective analysis.

BACKGROUND IgG4 related disease rarely affects the salivary glands and clinically is often confused with salivary gland malignancy. METHOD This is a retrospective study comprising 137 cases of chronic sialadenitis diagnosed in a histopathology department over 4 years. The morphology was assessed by reviewing the histology slides and the incidence of IgG4 related sclerosing sialadenitis was calculated. IgG and IgG4 immunohistochemistry was performed and mean IgG4 count/hpf and IgG4/IgG ratio were determined. Clinical findings were obtained from medical records. RESULTS Of the 137 cases reviewed, 3 cases showed diagnostic histological features of IgG4 related sialadenitis, these being: a prominent lymphoplasmacytic infiltrate, lobular fibrosis, acinar atrophy, obliterative phlebitis and mean IgG4 count of 86/hpf with mean IgG4/IgG ratio 65%. No further disease was documented at follow-up which ranged from 24 to 36 months. CONCLUSION The incidence of IgG4 related sialadenitis in the present study is 2%, indicating that it is a rare condition. Since there is no non-invasive diagnostic modality, either core biopsy or surgical excision is required for definitive histological diagnosis.