Computed tomography of orbital dermoids: a 20-year review.

AIM: To review the computed tomographic images of orbital dermoid cysts referred to our institution over a 20-year period.

MATERIALS AND METHODS: The CT images of 160 patients with histologically proven orbital dermoid cysts were reviewed and patient demographics and cyst characteristics were recorded.

RESULTS: A total of 160 dermoid cysts were seen, 87 were in male and 73 in female patients with mean ages of 29 and 27 years respectively. The lateral aspect of the orbit was the most common site (69%, 111/160). Eighty-five percent (136/160) had adjacent bone changes, 46% (73/160) were of lower CT attenuation than the water in the vitreous body, 14% (22/160) had calcification, 5% (8/160) had fluid levels, 73% (117/160) had a visible wall and 80% (129/160) had no soft tissue present outside the cyst.

CONCLUSION: Our study shows that orbital dermoids are frequently located at the lateral canthus. Bone sparing, calcification, fluid level, no visible wall and no abnormal soft tissue outside the cyst are infrequent. A CT attenuation similar to fat is relatively frequent. Although many lesions are typical, the range of appearances is wide.