In this case report, an 81-year-old former carpenter presented with unilateral deteriorating vision. Due to gradual worsening and involvement of the other eye, he was seen by an ophthalmologist and underwent both CT and MRI, which gave rise to suspicion of a sinonasal cancer. Nasal endoscopy revealed a tumour in the ethmoid bilaterally, and a biopsy showed intestinal type adenocarcinoma. This type of cancer is rare, but strongly associated with occupational exposure to wood dust. Symptoms are usually vague, and the diagnosis is made with some delay, which is reflected in a poor prognosis.