Systemic IgG4 Disease and Orbital Inflammatory Lesions Including Necrobiotic Xanthogranuloma
K Singh, CG Eberhart. Brown University, Providence, RI; Johns Hopkins Hospital, Baltimore, MD
Background: IgG4 disease is characterized by mass-forming lesions due to lymphoplasmacytic infiltrates rich in IgG4+ plasma cells with associated sclerosis and a raised serum IgG4 level. Systemic IgG4 disease related orbital inflammatory lesions are rare and poorly understood. We recently encountered a case of orbital necrobiotic xanthogranuloma(NXG) associated with confirmed systemic IgG4 disease. We analyzed the number of IgG4-positive plasma cells in this and an additional 16 orbital inflammatory lesions.
Design: Immunohistochemistry for IgG (polyclonal rabbit anti-human IGG, DAKO) and IgG4 (monoclonal mouse anti-human IGG4, ZYMED laboratories) was performed on formalin fixed, paraffin-embedded sections using standard techniques. IgG and IgG4 positive plasma cells were counted in random (maximum ten) high power fields (40X objective with 10X eyepiece).
Results: The table below summarizes our results for the 17 cases included in the study. The NXG(Figure1) in the confirmed case of systemic IgG4 disease had 119 IgG4 positive plasma cell per HPF (range 83 to 170) with a 55% mean percentage of IgG4 positive plasma cells (range 30% to 84%). The IgG4 positive plasma cell percentages in all other orbital inflammatory lesions were low and only one case of non-specific chronic dacryoadenitis with some sclerosis had 33 % IgG4 positive plasma cells in a single focus.
|Diagnosis||Age(range)||M:F||IgG4+ plasma cells/HPF(mean, range)||IgG+ plasma cells /HPF(mean , range)||IgG4/IgG Plasma cell %(mean , range)|
|Chronic non-specific dacryoadenitis(n=10)||15-62||1:4||3(0-50)||56(1-241)||3(0-33)|