We describe a case of Wegener's granulomatosis. The first symptoms included severe headache subsiding only after administration of dexamethasone. Despite a great number of diagnostic tests involving CT and MR of the head, the cause of the headache remained unknown. Because a chest x-ray revealed a nodule in the right lung, the patient was sent to our Clinic. Reevaluation of CT and MR pointed to a massive ethmoid sinusitis. 7-days' course of antibiotics and corticosteroids induced remission of the lung nodule. Several diagnoses were made: neoplasm, bacterial ethmoid sinusitis, trigeminal neuritis, thrombotic cavernous sinusitis and tuberculosis. Results of the ethmoid sinus biopsy together with a high c-ANCA concentration gave the correct diagnosis.