[Cranial idiopathic hypertrophic pachymeningitis associated with orbital pseudotumor: case report].

Hypertrophic pachymeningitis is a rare disorder characterized by meningeal thickness, that can be caused by infection, tumoral infiltration, inflammatory disorders or idiopathic. We report the case of a 40 year-old man that presented with longstanding headache and progressive bilateral visual loss and proptosis. Cranial and orbital magnetic resonance imaging revealed diffuse dural thickness and bilateral extraconal orbital lesion. Extensive investigation did not reveal any systemic condition. Histopathological study after meningeal and orbital biopsy disclosed a chronic inflammatory process compatible respectively with idiopathic hypertrophic pachymeningitis (IHP) and orbital pseudotumor. This case emphasizes that orbital involvement can occur in IHP and that its early identification is of great importance in order to improve the visual prognosis of this condition.