[Bilateral pseudotumoral proptosis as presenting sign of orbital hyper-IgG4-related disease].

Orbital hyper-IgG4 syndrome manifests most often as pseudo-tumoral bilateral proptosis. Elevated IgG4 levels are neither sensitive nor specific. Biopsy with immunohistochemical study is the key to diagnosis. Systemic steroid treatment is the gold standard, but recurrences may occur.