IgG4-Related Systemic Disease as a Cause of “Idiopathic” Orbital Inflammation, Including Orbital Myositis, and Trigeminal Nerve Involvement

A: A 56-year-old man had experienced several exacerbations annually over a 30-year period of left eyelid swelling, shown here as a festoon of edema collecting in the left lower eyelid (arrow). B: At the time of his last presentation there was the fullness of the left lower eyelid without a conspicuous collection of edema. C: On everting the eyelid, multi-nodular erythematous lobules of the palpebral lobe of the lacrimal gland (arrow) can be observed.

A: A computed axial tomogram discloses enlargement of the lateral rectus muscle (LR) and the lacrimal gland (LG). B: A coronal section shows thickening with irregular edges of the inferior rectus and oblique muscles (arrow). There is mucosal thickening of the left antrum. C: The left superior rectus and levator complex is swollen (crossed arrow). The small arrows indicate the optic nerves. The large uncrossed arrow below highlights an enlarged infraorbital nerve. D: A coronal section proceeding toward the orbital apex displays crowding of the optic nerves (arrows) simulating the myositis of Graves' disease. Thyroid studies were normal. E: On the left side there is widening of the pterygopalatine canal (uncrossed arrow) compared with that on the right (crossed arrow). There is also an increased soft tissue density in the left pterygopalatine fossa (double crossed arrow) signifying involvement of the trigeminal nerve.

A: A lymphoid infiltrate with associated eosinophilic fibrosis spills over into the adjacent orbital fat and effaces the lobules of the lacrimal gland (arrows). B: There are surviving acini of the lacrimal gland (LG) shown above, as well as interlobular ducts in the center of the field (arrows). C: The lymphocytes are small and there is periductal fibrosis (arrow). D: A germinal center (GC) composed of small germinal center cells is present toward the right, and a single duct with surrounding fibrosis is evident on the left (arrow). (Hematoxylin and eosin, A ×25, B ×100, C ×200, D ×200.)

A: CD20 immunostaining demonstrates multiple B-cell aggregates (arrows). B: Interconnecting tracts of CD3-positive T-lymphocytes are also present within the lesion. C: Bcl-2 fails to stain follicular center cells, whereas cells of the mantle zone are positively stained. The inset reveals a tight network of CD23-positive dendritic cells within the follicular centers. D: Myriad IgG4-positive plasma cells are present throughout the lacrimal infiltrate. Polyclonality is established by the presence of both kappa (E) and lamda (F) light chain staining. The arrows point out surviving elements of the lacrimal gland. (Immunoperoxidase staining, diaminobenzidine chromogen, A ×100, B ×100, C ×100, Inset ×200, D ×100; in situ hybridization, E ×100, F ×100.)