Basal cell adenocarcinoma is a rare and relatively recently characterised malignant salivary gland tumour. It accounts for 5 per cent of parotid gland tumours and 1 per cent of salivary gland malignancies. It is very rarely documented in anatomical sites other than the major salivary glands. Basal cell adenocarcinoma has only been described once before in the ethmoid sinus.

We report a case of basal cell adenocarcinoma in the ethmoid sinus, extending into the right orbit and anterior cranial fossa. We describe the clinical aspects of the patient's management and detail the histopathological features of this very rare diagnosis.