Bone thinning in frontal mucocele.

Sixteen cases of frontal mucocele are reviewed. Bone thinning leading to destruction of the sinus floor was shown to be a feature. It usually affects the superomedial margin of the orbital roof first, due to pressure on the area where the sinus wall is thinnest. Demonstrable thinning of either anterior or posterior sinus walls--a cardinal sign of frontal mucocele, is best shown by means of underpenetrated lateral radiographs. All other conventional radiographic signs of frontal mucocele, including lucency of the affected sinus, were found to be non-specific. The presence of an osteoma in a site likely to obstruct the frontonasal duct is a valuable adjunct to diagnosis.