Adenoid cystic carcinoma of the maxillary sinus: CT and MR imaging findings

Objective The purpose of this study was to determine whether adenoid cystic carcinomas (ACCs) of the maxillary sinus have features on CT and MR imaging. Materials and methods Nine patients with histopathologically proved maxillary sinus ACCs were included. The growth pattern was classified as expansile or destructive types on the basis of CT images. CT images were also reviewed for adjacent bony defects and MR images were reviewed for tumor extension. Fluid accumulation in the ipsilateral maxillary sinus was also assessed. Results The tumors had caused adjacent bony expansion with minimal bony defects in 4 patients whereas those in the remaining 5 patients had caused extensive destruction of adjacent bones comprising the maxillary sinus walls. Nasal cavity invasion was observed in 7 patients, retroantral fat pad invasion in 5, pterygopalatine fossa invasion in 4, and orbital invasion in 3. All 4 expansile ACCs were accompanied by accumulation of a small amount of fluid in the surroundings of the tumors, which was revealed as hyperintensity on T1-weighted images. Conclusion The growth pattern of maxillary sinus ACCs can be classified into an expansile type with minimal bony defects and a destructive type with extensive bony defects.