[Coexistence of Lung Adenocarcinoma and Non-caseous Epithelioid Granuloma Possibly due to Systemic Sarcoidosis in the Same Lesion].

A lung cancer coexists with non-caseous epithelioid granulomas (NEG) in the same lesion is uncommon. A 62-year-old female was referred to our hospital for examination of a right lung S3 nodule which was recently increasing in its size. Positron emission tomography-computed tomography (PET-CT) examination revealed positive signals at the S3 nodule as well as mediastinal lymph nodes, apex of heart and right pleura. Pathological examination revealed the S3 nodule coexisting with both adenocarcinoma and NEG. The differential diagnosis between the systemic sarcoidosis and sarcoid reaction is usually important in such a case. Since the pleura and mediastinal lymph nodes contained many NEGs, the adenocarcinoma arising based on the systemic sarcoidosis was possibly suggested in the present case.