Amyloidosis concurrently involving the sinonasal cavities and larynx.

Localized amyloidosis is an uncommon benign disorder. The purpose of this report is to present the case of a 21-year-old man who had localized amyloidosis simultaneously involving the sinonasal cavities and the larynx. The rarer sinonasal lesion demonstrated CT findings of adjacent "fluffy" bone changes, possibly representing a new finding suggestive of this disorder. At MR imaging, the amyloid had signal intensity similar to that of skeletal muscle on T1- and T2-weighted images. After contrast material administration, the amyloid enhanced at most minimally, but peripheral enhancement about the mass was present. The importance of this case lies in the multifocal presentation of this uncommon disorder, and the imaging findings herein may provide a new sign of this paranasal sinus disease.