Unusual Involvement of IgG4-Related Sclerosing Disease in Lacrimal and Submandibular Glands and Extraocular Muscles

Chronic sclerosing sialadenitis, also known as Kuttner tumor, is a chronic inflammatory disease of the salivary glands that is reported in a few cases in medical literature. Recent reports suggest that certain aspects of sclerosing diseases, including chronic sclerosing sialadenitis or dacryoadenitis, should be classified under immunoglobulin G4 (IgG4)-related sclerosing disease based on immunohistochemical studies. This study reports an unusual case of IgG4-related sclerosing disease appearing simultaneously in the lacrimal glands, submandibular glands, and extraocular muscles. A 56-year-old male presented with complaints of bilateral eyelid swelling and proptosis that began two years ago. Computed tomography confirmed that bilateral submandibular enlargements also existed five years ago in the subject. Orbital computed tomography and magnetic resonance imaging revealed bilateral lacrimal gland enlargement and thickening of extraocular muscles. Typical findings of chronic sclerosing dacryoadenitis were revealed upon pathologic exam of the right lacrimal gland. Immunostaining revealed numerous IgG4-positive plasma cells. Through these clinical features, we make a diagnosis of IgG4-relataed sclerosing disease in the subject.

IgG4-Related Sclerosing Disease, an Emerging Entity: A Review of a Multi-System Disease

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a recently defined emerging entity characterized by a diffuse or mass forming inflammatory reaction rich in IgG4-positive plasma cells associated with fibrosclerosis and obliterative phlebitis. IgG4-RSD usually affects middle aged and elderly patients, with a male predominance. It is associated with an elevated serum titer of IgG4, which acts as a marker for this recently characterized entity. The prototype is IgG4-related sclerosing pancreatitis or autoimmune pancreatitis (AIP). Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, however practically any organ can be involved, including upper aerodigestive tract, lung, aorta, mediastinum, retroperitoneum, soft tissue, skin, central nervous system, breast, kidney, and prostate. Fever or constitutional symptoms usually do not comprise part of the clinical picture. Laboratory findings detected include raised serum globulin, IgG and IgG4. An association with autoantibody detection (such as antinuclear antibodies and rheumatoid factor) is seen in some cases. Steroid therapy comprises the mainstay of treatment. Disease progression with involvement of multiple organ-sites may be encountered in a subset of cases and may follow a relapsing-remitting course. The principal histopathologic findings in several extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, along with atrophy and destruction of tissues. Immunohistochemical staining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). IgG4-RSD may potentially be rarely associated with the development of lymphoma and carcinoma. However, the nature and pathogenesis of IgG4-RSD are yet to be fully elucidated and provide immense scope for further studies.