A clinical case of orbital inflammatory pseudotumor as the primary expression of eosinophilic angiocentric fibrosis.

Eosinophilic angiocentric fibrosis (EAF) is an infrequent and slowly progressive disease, represented by fibroinflammatory lesions of unknown origin, which mainly involves the sinonasal structures and upper respiratory tract. Occasionally, it can affect the orbit and ocular adnexa causing symptoms such as proptosis, globe displacement and periorbital edema. In very rare cases, ocular manifestation as an orbital inflammatory pseudotumor can be the primary localization of the disease. Current literature proposes a relation between EAF and immunoglobulin G4-related disease spectrum. We describe the case of a 69-year-old man presented with antecedents of left periorbital edema, epiphora and retroocular pain. Examination showed a nonaxial proptosis, severe limitation in left eye adduction and lateral globe displacement. Orbital imaging revealed a left medial orbital mass with involvement of the inferior rectus and the medial rectus muscles. An orbital biopsy of the mass illustrated an inflammatory infiltrate with a notable eosinophilic component, "onion-skin appearance" of vessels and surrounding concentric fibrosis, highly suggestive of EAF. Further investigations showed a high expression of IgG4 and excluded other possible diseases. There was a favorable evolution of the orbital inflammatory pseudotumor following a 4-month treatment course with oral glucocorticoids.