A correct diagnosis is essential to ensure adequate treatment and attain an acceptable balance between cost and effectiveness.

Ameloblastomas are the most frequent odontogenic tumours, accounting for 1% of all tumours of the maxilla and mandible. Sinonasal ameloblastomas are most common between the ages of 55 and 65, and mandibular ameloblastomas between 40 and 50. Incidence is higher in males than in females, and there are no differences between races. These locally aggressive tumours originate in the mandible in 80% of cases and in the maxilla in 15-20%. We report an unusual primary nasosinusal ameloblastoma presented in a 68-year-old male. The tumour was completely resected by (para)lateral rhinotomy and treated with postoperative radiotherapy. Histological analysis demonstrated a plexiform ameloblastoma. The patient remains well without disease after 50 months of postoperative follow-up.

Non-Hodgkin's lymphoma originating from mucosa-associated lymphoid tissue has been connected with autoimmune disease. These tumours often arise in gastric mucosa and are extremely rare in airway mucosa. Three cases of mucosa-associated lymphoid tissue lymphoma in the cavum have been reported in the literature. A 52-year-old male with rheumatoid arthritis presented with an 8-month history of nasal obstruction and recurrent nasal blood discharge. On physical examination a bulky mass was observed in the nasopharynx. CT demonstrated a soft tissue lesion in the nasopharynx without bone destruction. MRI showed a contrast-enhanced mass with extension to the left pterygoid muscle. Biopsy revealed a low-grade B-cell lymphoid tumour of the marginal zone. The patient received six cycles of cyclophosphamide, vincristine and prednisone with adriamycin treatment, together with intracranial methrotrexate as a prophylactic measure. After 48 months of follow-up there was no evidence of disease and a control MRI scan was normal. The prognosis of this type of tumour is unpredictable and there are too few cases to enable definitive conclusions to be drawn.