SUMMARY:The frontal process of the maxilla occasionally shows a localized FD-like appearance. The purpose of this study was to determine its prevalence and findings on CT. A retrospective study of 1000 consecutive paranasal sinus CT scans was preformed on outpatients without a history of trauma or previous surgery in our hospital during 6 months. CT images were interpreted independently by 2 experienced head and neck radiologists on a PACS system in a bone window setting. Of the 1000 patients (546 males; 454 females), 51 (5.1%,41 males and 10 females) had an FD-like appearance in the frontal process of the maxilla. There was a statistically significant difference between sexes (P Ͻ .001). Twenty-nine (56.9%) entities arose from the right frontal process and 22 (43.1%) from the left frontal process. These entities, with well-defined margins, were located at the base of the frontal process of the maxilla, appearing as an ovoid or triangular configuration on axial-plane CT and as a spindle or elliptic shape on the coronal plane. The mean maximal diameter was 9.8 mm (range, 3.6 -16.1 mm). These entities exhibited a pagetoid appearance (type I) in 37 (72.5%), a ground-glass appearance (type II) in 8 (15.7%), and a cyst-like appearance (type III) in 6 (11.8%) patients on CT. The FD-like appearance of the frontal process of the maxilla is not rare and can be readily detected by CT.
ABBREVIATIONS: FD ϭ fibrous dysplasia
During the past 10 years, we have incidentally encountered a few people with an FD-like appearance of the frontal process of the maxilla by paranasal sinus CT in our daily practice. These individuals usually presented to the ear, nose, and throat clinic with rhinosinusitis symptoms and underwent paranasal sinus CT scans. On the basis of outpatient medical records, they had no facial deformities on physical examination. To the best of our knowledge, no relevant studies on the subject have been reported in the literature to date.1-6 Knowledge of the osseous appearance in this region could help radiologists and clinicians increase their awareness of the variant or asymptomatic FD, avoiding confusion with tumor or infection. For us, there has been some recent interest in the appearance of the frontal process of the maxilla. This prompted our study to determine the prevalence and features of it on paranasal sinus CT scans of outpatients in North China.
Materials and Methods
PatientsThis study was approved by the institutional review board. A retrospective review of paranasal sinus CT scans of 1000 consecutive outpatients who were consecutively selected by a PACS system in our hospital between August 1, 2008, and January 31, 2009, was performed. All these patients were referred for CT due to clinical symptoms, presumably rhinosinusitis. Their clinical medical records were reviewed, and they had no history of trauma or prior surgery.
CT TechniqueCT images were acquired in both the axial and coronal planes by using a Brilliance 64-section CT scanner (Philips Healthcare, Best, the Netherlands). The imaging parame...