[Clinical and radiological features and clinical course of orbital myositis]

Orbital myositis is idiopathic inflammation of the extraocular muscles in the absence of thyroid orbitopathy and often is included under broad description pseudotumor. We report here a series of three cases. Data from literature, combined with our own results yield a distinguishing pattern of orbital myositis suggesting that the term "orbital pseudotumor" is no longer a useful concept. The diagnostic criteria purposed here are: acute orbital pain exacerbated on eye movement; enlargement of one or more extraocular muscles with the respect of other orbital structures on muscle CT scan; absence of clinical and biological thyroid dysfunction: absence of signs of anterior uveitis or scleritis or visual decrease; rapid response to immunomodulator treatment.