Radiology, Vol 165, 475-478, Copyright © 1987 by Radiological Society of North America
Orbital dermoids: features on CT
RA Nugent, JS Lapointe, J Rootman, WD Robertson and DA Graeb
Department of Radiology, University of British Columbia, Vancouver, Canada.
The computed tomographic (CT) features of orbital dermoids were
retrospectively reviewed in 17 patients; 15 of the lesions were proved
histologically. On the basis of clinical and CT features, the tumors were
classified as superficial or deep. All but one were extraconal in location.
Seven lesions appeared cystic; only six showed typical fat density. The
presence of a margin or rim, often partially calcified, was identified in
ten lesions. Irregular scalloping of adjacent bone was a highly suggestive
feature, occurring with 11 dermoids. Other bone changes, such as linear
defects, thinning, or sclerosis, also occurred. Superficial dermoids showed
less apparent bone changes. An extraconal orbital lesion associated with
adjacent bone thinning or notching should raise the possibility of a
dermoid, especially if a rim with calcification is seen. The appearance is
pathognomonic if fat density is also present.
