Amyloidosis is a rare condition characterized by the deposition of abnormal protein filaments into the extracellular tissue. Only 16 cases of true primary idiopathic amyloidosis localized in the nose and the paranasal sinuses have previously been reported. We present a case of localized amyloidosis involving the sinonasal cavities and the nose in a 53-year-old woman. Our patient was operated on as a typical case of chronic rhinosinusitis with polyps, but after 2 years, the patient came back with severe symptoms of nasal obstruction and pain in the frontal and maxillary regions with proptosis of both eyes. Magnetic resonance imaging revealed sinonasal-intraorbital masses. Primary amyloidosis (AL type) was confirmed by tissue biopsy. A systemic workup for additional amyloid deposits revealed no evidence of other diseases. Extended surgery produced a symptomatic improvement.