[A case of sinonasal inverted papilloma with malignant transformation and distant metastasis: a 10-year follow-up report].

Sinonasal inverted papilloma（SNIP） is a kind of benign tumor originating from the nasal cavity and paranasal sinuses, accounting for 70% of papillomas. The incidence of the disease is more common in males, with an average age of 50-60 years. It is most likely to occur in unilateral maxillary sinus and ethmoid sinus, followed by sphenoid sinus and frontal sinus.It has the characteristics of local invasion, high recurrence rate and malignant tendency, and most malignant transformation into squamous cell carcinoma. Endoscopic nasal resection and appropriate adjuvant therapy can help to reduce the recurrence rate and inhibit further deterioration. We report the results of a 10-year follow-up of a SNIP patient, including the clinical manifestations, recurrence course and treatment plan during the 10 years. The patient underwent multiple nasal endoscopic surgeries, and had a recurrence of multiple focal attachment pattern, and finally had direct invasion and distant metastasis. Tumor recurrence and further deterioration persisted despite the use of a comprehensive treatment.