A Case of Primary Systemic Amyloidosis Involving the Sinonasal Tract.

We present a case of primary systemic amyloidosis diagnosed by endoscopic sinus surgery. A 75-year-old woman had blurred vision in her left eye; computed tomography and magnetic resonance imaging showed shadows of the bilateral paranasal sinuses. Endoscopic sinus surgery was performed, and amyloidosis was diagnosed by histopathology. She had previously been diagnosed with amyloidosis of the stomach, and therefore, she was diagnosed with primary systemic amyloidosis. A systemic workup for additional amyloid deposits revealed no evidence of other diseases. The patient remained under follow-up without further treatment, as no further amyloid deposition or progression of the lesions was seen. Amyloidosis is a rare condition characterized by the deposition of abnormal protein filaments in the extracellular tissue. Generally, systemic amyloidosis does not involve the head and neck region, and the presence of amyloid in the nasal and paranasal sinus mucosa is more likely to be indicative of a localized process. However, in our patient, the lesions were located in both the sinonasal tract and the stomach, indicating systemic amyloidosis. To our knowledge, there have been no previous reports of systemic amyloidosis involving the sinonasal tract, and therefore, we consider this case to be extremely rare.