Chronic exposure to particles caused bronchioloalveolar carcinoma in a patient with cryptogenic organizing pneumonia evaluated by elemental analysis.

An 81-year-old Japanese man had organizing pneumonia (OP), and he had worked as a painter and had a history of exposure of various paints over 20 years. The major features on computed tomography (CT) in patients were cryptogenic organizing pneumonia (COP) showing airspace consolidation, and air bronchograms were consistent finding in consolidation in right lung of S¹⁰. Such parenchymal abnormalities were clinically and pathologically diagnosed COP and the lesion was improved by corticosteroid therapy. About 1.5 years later, similar shadows emerged in new locations of right S⁴ and left S⁸, and these were bronchioloalveolar carcinoma (BAC) classified as adenocarcinoma. BAC causes similar X-ray changes to COP and inflammation accompanying BAC can also respond to corticosteroids, which may lead to delay in the diagnosis of BAC associated with COP. These radiological features lead to difficulty in making a diagnosis of new parenchymal diseases. The present patient had been painter, and metals of carcinogens were proven in both tissue of COP and BAC. Here, we reported a painter with COP and new-onset BAC who had been exposed to particles proven by elemental analysis. The combination of COP with BAC is considered uncommon, but the risk of BAC may increase when there is a history of particle inhalation.