Pseudotumor of the orbit - Clinical, pathologic, and radiologic evaluation

Pseudotumor, Graves' disease, and lymphoproliferative disease are the most common ophthalmologic disease entities requiring evaluation by CT and MR im aging. A history of acute onset, pain, swelling, proptosis, and response to steroids are the classical findings. The radiologic findings are categoriz ed according to location into dacryoadenitis, myositis, and sclerouveitis, with and without associated infiltrations. The inflammatory infiltrate, whi ch is composed of polymorphic leukocytes, lymphocytes, and plasma cells int erspersed with a variable amount of fibrovascular tissue, may be diffuse or localized. The preferred radiologic method used for assessment of pseudotu mor is CT. MR imaging, however, is indicated for evaluation of the Tolosa-H unt syndrome, which is characterized by an inflammatory infiltrate in the o rbital apex and cavernous sinus leading to cranial nerve involvement with o phthalmoplegia. The clinical and radiologic constellation of findings allow s a definitive diagnosis in most cases.