Systemic tumor embolism mimicking gefitinib ('IRESSA')-induced interstitial lung disease in a patient with lung cancer.

We describe a 55-year-old man with advanced adenocarcinoma of the lung who received gefitinib ('IRESSA'). After gefitinib administration for 7 months, computed tomography scan of the chest demonstrated diffuse ground glass opacity and he was suspected to have developed gefitinib-induced interstitial lung disease (ILD). However, transbronchial lung biopsy (TBLB) revealed tumor cells in the middle-size lung vessels. Afterwards, multiple infarctions of the brain, spleen and left kidney were detected. Then, he was considered to have developed systemic tumor emboli, a rare complication. The clinical presentation of this patient was difficult to discriminate from that of ILD, and TBLB was useful in the differential diagnosis.