Neuroimaging diagnosis of Tolosa-Hunt syndrome: MRI contribution

To present our experience in the neuroradiological diagnosis of six patients with Tolosa-Hunt syndrome.

Computerized tomograms and MRI, with and without contrast enhancement, of the cranium and orbits of patients fulfilling IHS criteria for the diagnosis of Tolosa-Hunt syndrome were analyzed.

Standard CT scan, with and without contrast enhancement, disclosed an enlarged cavernous sinus in one patient and was normal in the remaining five. In comparison, MRI was clearly abnormal in the four patients on whom it was performed, showing a convex enlargement of the symptomatic cavernous sinus by an abnormal tissue isointense with gray matter on short TR/TE images and iso-hypointense on long TR/TE scans. This abnormal tissue markedly increased in signal intensity after contrast injection and, in two patients, extended into contiguous regions, mainly the orbital apex and subtemporal fossa ipsilaterally. One patient had follow-up studies after successful treatment with corticosteroids. Although diminished in size, the abnormal tissue was still visible on MRI after 3 months of treatment and only disappeared after 6 months of treatment.

These MRI findings help in the differential diagnosis of the Tolosa-Hunt syndrome from conditions such as meningioma, lymphoma, and sarcoidosis, as well as confirming the similarities of the Tolosa-Hunt syndrome and orbital pseudotumor. In the presence of painful ophthalmoplegia, the finding by MRI of cavernous sinus enlargement, with the herein described signal and extension characteristics and slow resolution with corticosteroid treatment, is highly suggestive of the Tolosa-Hunt syndrome.