An unusual presentation of inverted papilloma: case report and literature review.

OBJECTIVE: Inverted papilloma is a rare but locally aggressive tumour with the potential for malignant transformation. Intracranial extension or complications secondary to inverted papilloma are extremely rare. We report a case of inverted papilloma with a large frontal sinus mucocele eroding the frontal sinus, which presented with sudden neurological compromise. A literature review on intracranial extension of such tumours is also included.
METHODS: A Medline search of articles, using the terms 'inverted papilloma', 'Ringertz tumour', 'intracranial extension' and 'complication'. Suitable references from the collected articles were also reviewed. Articles published in English were selected and reviewed.
RESULTS: A total of 10 cases was identified. Intracranial spread was more commonly seen in recurrent cases, especially if the recurrence involved the cribriform plate, fovea ethmoidalis or orbits. Cases with extradural disease seemed to have a better prognosis than those with intradural spread.
CONCLUSIONS: Intracranial involvement of inverted papilloma is extremely rare, and is usually seen in recurrent cases. This case report highlights an unusual but serious case of inverted papilloma presenting with acute neurological deterioration secondary to a large frontal sinus mucocele eroding the frontal sinus. A literature review on intracranial extension of inverted papilloma indicated that common sites of intracranial spread include the cribriform plate, fovea ethmoidalis and orbits. The prognosis for patients with such tumours depends on the type of dural involvement, with intradural extension carrying a poorer prognosis.