Reversible hyposmia caused by intracranial tumour

Two patients with hyposmia caused by an intracranial tumour recovered olfac tory functions after craniotomy. The first case was a 68-year-old male with a tumour metastasized from the lung to the right frontal lobe. The second case was a 75-year-old male with meningioma of the right frontal lobe. Resu lts of T & T olfactometry and venous olfaction tests also indicated suspect ed central hyposmia. Magnetic resonance imaging (MRI) indicated compression of the frontal lobe by intracranial tumour. Pressure on the olfactory cent re located in the frontal lobe produced hyposmia. Decompression of the fron tal lobe by craniotomy improved the sense of smell. Therefore, some cases o f olfactory disturbance caused by intracranial tumour may be reversible if they are the result of simple compression of the olfactory centre.