Squamous cell carcinoma arising in inverted papilloma.

A retrospective review of all cases of inverted papilloma at the University of Michigan from 1975 to 1992 revealed 51 cases of inverted papilloma. Of these, 14 (27%) had an associated squamous cell carcinoma (SCC). Eight (16%) were metachronous and 6 (11%) were synchronous. At a mean follow-up of 53 months, the disease-free survival of patients with carcinoma limited to the nasal cavity and paranasal sinuses was 57% (4/7) compared to 14% (1/7) of those patients presenting with disease extending beyond the nasal cavity and paranasal sinuses. The data also support the lateral rhinotomy approach with medial maxillectomy and ethmoidectomy as a minimum procedure followed by postoperative radiation therapy. The mean interval between the diagnosis of inverted papilloma and development of SCC was 63 months (range, 6 months to 13 years). Therefore, long-term follow-up with clinical examination and computed tomography (CT) scan is indicated for all patients with inverted papilloma.