We reported a patient with an extensive benign sinonasal squamous papilloma in the right nasal cavity with involvement of right sphenoid, ethmoid, maxillary sinuses and intracranial extension. This tumour is rare with very few reported cases in the literature of such extensive in nature. The tumour is excised completely with combined endoscopic transnasal and transcranial approaches. The patient remains disease free at a year interval of follow-up.