A case of sphenoid sinus mucocoele following radiotherapy in a patient with nasopharyngeal carcinoma is reported. Diagnosis was made by radiological investigation and confirmed at surgery performed via a sublabial transeptal approach. Its content was completely removed and continuous drainage of the sinus was maintained by an indwelling tube. It is felt that the sphenoid mucocoele developed as a result of occlusion of the sinus ostium by scarred mucosa following radiotherapy.

The term tumefactive fibroinflammatory lesion is used to describe an unusual fibrosclerosing disorder that behaves in a malignant way clinically but is histologically benign. Lesions in the head and neck are believed to be part of the broader fibrosclerosing syndrome which include pseudotumour of the orbit, Reidel's thyroiditis, sclerosing cholangitis and mediastinal fibrosis. Clinical diagnosis is often difficult and relies heavily on histopathology. Steroid therapy is suggested as the first line of management, while surgery or radiation therapy is reserved for failures.