[Orbital apex syndrome without MRI lesion caused by ANCA-associated vasculitis].

A 73-year-old man developed double vision and a progressive loss of visual acuity of the left eye over one week. Examination showed disturbances of the left II, III, IV, and VI cranial nerves, that is, an orbital apex syndrome. A brain MRI showed abnormal T2-high signals in the right maxillary sinus and the left mastoid cells without abnormalities in the left orbital apex and the surroundings. Laboratory examination showed an elevated erythrocyte sedimentation rate and a positive perinuclear anti-neutrophil cytoplasmic antibody (MPO-ANCA). After two courses of methyl-prednisolone pulse treatment, his external ophthalmoplegia fully recovered and he regained his left eye's sight. MPO-ANCA was negative and MRI abnormalities were disappeared after treatment. Two years later, the patient developed upper respiratory symptoms associated with an elevation of MPO-ANCA titer, and rapidly progressive renal failure. Renal biopsy specimen showed fibrinoid necrosis with periarteriolar neutrophil infiltration, which suggested that the patient suffered from ANCA-associated vasculitis probably of Wegener's granulomatosis or microscopic polyarteritis. ANCA-associated vasculitis may present with a focal neurological syndrome such as the orbital apex syndrome without a lesion detectable with MRI.