Sarcoidosis and lung cancer.

BACKGROUND Although sarcoidosis as well as lung cancer are frequently encountered common diseases, their metachronous or synchronous occurrence in the same patient is very rare. METHODS The charts of lung cancer patients, diagnosed between 1980 and 2007 in our hospital, were reviewed. RESULTS We found 3 cases with sarcoidosis and lung cancer. The first case had lung cancer 16 years after the diagnosis of sarcoidosis. The second case had two different metachronous lung cancers 18 and 10 years after the diagnosis of sarcoidosis. The third case detected these two diseases simultaneously. In simultaneously detected cases, it is difficult to determine whether noncaseating epithelioid cell granulomas coexisting with lung cancer represent sarcoid reaction or genuine systemic sarcoidosis. CONCLUSIONS Either causality or coincidence, lung cancer, a condition that can be observed in patients with sarcoidosis, should be considered in the differential diagnosis when suspicious findings of it are discovered.