Sinonasal undifferentiated carcinoma – a rare cause of proptosis in elderly

Sinonasal undifferentiated carcinoma is a rare and extremely aggressive sinonasal tract malignancy. It is a rapidly enlarging tumour and a highly destructive lesion. We hereby report a 71-year-old Malay male with progressive left proptosis for one month, associated with reduced vision in the left eye, intermittent diplopia and anosmia. He was later diagnosed as having sinonasal undifferentiated carcinoma. The patient subsequently underwent a series of radiotherapy and showed improvement following treatment. This case was reported to highlight the importance identifying this entity and emphasise that sinonasal undifferentiated carcinoma should be considered in an elderly patient with proptosis associated with nasal symptoms.