Inverted papilloma (IP) of the sinonasal cavity occurs most commonly in the fifth to seventh decades of life, and accounts for 0.5–4% of all primary nasal tumors.
We report the case of a 60-year-old man who was diagnosed as having benign IP with intracranial extension. The patient was treated by sinonasal IP resection several times, however, each time, the tumor recurred. Eventually, as the tumor extended to the nasal cavity, right maxillary sinus and bilateral ethmoidal sinuses, we performed endoscopic sinus surgery and skull base resection. However, the tumor recurred again and extended into the skull. Finally, we performed skull base operation with craniotomy and administered postoperative radiation therapy to achieve complete control of the tumor. Until now, 12 months since completion of the last treatment, there has been no evidence of recurrence, and no evidence of brain dysfunction.
IP with intracranial extension without malignant transformation is uncommon. However, according to some reports, once it occurs, the mortality rate is 30–40%. Aggressive treatments, such as skull base operation with craniotomy and/or radiotherapy, are needed to achieve complete recovery.
