Radiological changes associated with inverted papilloma of the nose and paranasal sinuses.

Inverted papilloma is an uncommon benign tumour of the nose and paranasal sinuses which has a characteristic histological pattern, high recurrence rate after surgery and may undergo malignant change. The X-ray features are reviewed in 60 patients with histologically confirmed tumours. Plain X-ray appearances were negative or non-specific in nearly half the patients. The changes shown on hypocycloidal tomography and on CT scan are more specific. A mass in the middle meatus of the nasal cavity extending into the adjacent maxillary antrum is highly suggestive of the tumour. Other features not hitherto reported are the presence of calcified areas within the tumour mass demonstrated by CT, and sclerosis and deformity of the walls of the sinuses involved by tumour.