Sinonasal inverted schneiderian papilloma presenting as a large intraoral lesion.

Sinonasal inverted schneiderian papilloma (ISP) is a rare tumour, which almost exclusively arises from the mucosa lining, the nasal cavity and the paranasal sinuses. The tumour in its early stages presents as an asymptomatic mass, which may be discovered during routine examination. Large lesions usually measure a few millimetres to centimetres in size and show symptoms such as nasal blockade, recurrent sinusitis, postnasal drip, anosmia, epistaxis, facial pain and headache. Lesion presenting as a large oral mass is extremely rare and may cause diagnostic dilemma, resulting in misdiagnosis. This report describes a rare case of ISP presenting as large intraoral lesion, with wide area of facial skeletal involvement. Diagnosis and management of the pathology has also been highlighted. © BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.