Asymptomatic iris metastasis of small-cell lung cancer

A 70-year-old man was diagnosed with small-cell lung cancer (SCLC) of the left upper lobe, with a TNM classification of cT4N3M1b (PUL, OSS, BRA, HEP). A single asymptomatic brain metastasis 1 cm in diameter was also identified. The patient underwent four cycles of cisplatin plus irinotecan therapy, with a total effect of partial response. Complete remission of the brain metastasis was also achieved, and whole-brain radiation therapy (WBRT) was postponed at the request of the patient. Six months after diagnosis, he was admitted to our hospital with a major complaint of dizziness. Computed tomography showed enlargement of the primary lesion and multiple brain metastases. WBRT was started, but performance status did not improve. While undergoing WBRT, the patient complained of blurred vision. The ophthalmologist found a metastasis on the right iris by chance, although blurred vision was caused by detachment of the left retina. Two months later, the patient died of respiratory failure. Autopsy histologically confirmed the iris metastasis of SCLC. Cases of iris metastasis diagnosed before death are rarely reported. Iris metastases are estimated to account for 9 % of uveal metastases. This may suggest that many iris metastases have few clinical signs and are difficult to diagnose. Asymptomatic iris metastases, particularly among patients with SCLC, are thus likely to be underdiagnosed. Ocular metastasis should be considered when a cancer patient complains of visual disturbance.