Sinonasal inverted papillomas: recurrence, and synchronous and metachronous malignancy.

INTRODUCTION: Inverted papillomas are relatively rare, benign epithelial tumours of the nasal cavity which generate considerable interest because they are locally aggressive, have a tendency to recur and are associated with malignancy. AIMS: To review our experience of the management of inverted papillomas, and to review the literature in order to evaluate recurrence rates, rates of synchronous and metachronous carcinoma, and outcomes of treatment, both endoscopic and conventional.
METHODS: We retrospectively reviewed all cases of inverted papilloma that presented to our unit, a tertiary referral centre, over a 20-year period from 1985 to 2005. A Medline review of the literature was performed to identify published case series of inverted papillomas. We undertook a critical analysis of the literature.
RESULTS: We treated 65 patients with inverted papilloma over the 20-year period, with a mean follow up of five years (range one to 20 years). Fifty-eight patients initially underwent nasal biopsy, often with polypectomy. Thirty-six had endoscopic surgery, with five (14 per cent) suffering recurrence, whilst 16 had a lateral rhinotomy and medial maxillectomy, of which four (25 per cent) suffered a recurrence. Seven septal inverted papillomas required local resection, with no subsequent recurrences. There were seven (11 per cent) synchronous and two metachronous malignancies.Sixty-three case series with adequate data were identified from the literature. There were 163 (7.1 per cent) cases of synchronous carcinoma, out of 2297 cases. Metachronous carcinomas were reported in 74 out of 2047 cases, representing a transformation rate of 3.6 per cent. However, the true population base for these figures is uncertain, given that many series were reported from tertiary centres, where recurrent and problematic cases are likely to be over-represented. The recurrence rates were 12.8 per cent for endoscopic procedures, 17.0 per cent for lateral rhinotomy with medial maxillectomy, and 34.2 per cent for limited resections such as nasal polypectomy and Caldwell-Luc approaches. No significant association between atypia or dysplasia and recurrence or malignant transformation was found. The mean time taken to develop a metachronous carcinoma was 52 months (range six to 180 months). The estimated malignant potential for recurrent disease was up to 11 per cent.
CONCLUSION: Patients with inverted papilloma should undergo thorough surgery to remove all mucosal disease, most probably by the endoscopic, endonasal route when complete resection is possible. Cases demonstrating atypia or dysplasia may be treated by the endoscopic route. Recurrent disease and metachronous carcinoma can develop after a prolonged period of time. Long-term follow up is recommended to detect recurrence, as disease can become quite extensive before it becomes symptomatic.