Unilateral endocrine exophthalmos. Diagnostic problems in association with computed tomography

Swollen orbital extraocular muscles may mimic an orbital apex tumor on computed tomography. In five of our patients, in spite of highly suggestive findings on CT scanning, indicating the presence of an orbital apex lesion, the correct diagnosis proved to be endocrine exophthalmos. The value of complementary CT projections and of orbital ultrasonography to assist in the differential diagnosis is discussed, and the additional contribution of orbital phlebography for the confirmation of lesions in the orbital apex is emphasized.