Tolosa Hunt Syndrome: MRI Findings.

Tolosa-Hunt syndrome (THS) is an idiopathic inflammatory condition involving the cavernous sinus and orbital apex with an incidence of 1 case per million per year. We report on a case of a 70-year-old male with atypical MRI findings, vision loss, and painless ophthalmoplegia.  Ophthalmic evaluation revealed his best-corrected visual acuity was 20/40 in the right eye and counting fingers at a 0.5-foot distance in the left eye. External examination of the left eye revealed limited ocular movement, proptosis, and a positive relative afferent pupillary defect. Complete blood count, inflammatory markers, and full biochemistry tests, including thyroid and liver function tests, were within the normal range. A magnetic resonance imaging of the orbits with and without contrast demonstrated a homogenously enhancing lesion at the posterior intraconal compartment of the left orbit, extending to the orbital apex with the involvement of the adjacent extraocular muscles. The patient was started on intravenous methylprednisolone 60 mg daily and later discharged on prednisone 5 mg daily with partial symptom improvement on follow-up. Resection and biopsy revealed a soft tissue lesion with mixed inflammatory infiltrate. The clinical, pathological, and imaging findings favored the diagnosis of THS.