Bilateral transitional-type inverted papilloma of the nose and paranasal sinuses.

An uncommon bilateral transitional-type inverted papilloma of the nose and paranasal sinuses is presented, and the salient features of the lesion are discussed. The patient is well and without any signs of recurrence in either side of the nose more than two years after the first diagnosis and complete surgical excision of both tumours. Commonly unilateral, this tumour may occasionally be bilateral. In the present communication an uncommon case of bilateral inverted transitional-type papilloma, with a long history of allergy, is described with some comments on its pathogenesis.