[A case of mucinous cystic adenocarcinoma of the lung with signet-ring cells].

A 70-year-old male case of mucinous cystic adenocarcinoma of the lung with signet-ring cells was reported. Patient was operated with diagnosis suspicious lung cancer by the specimen from TBLB. But, intraoperative rapid pathological-diagnosis was confused us for no cellular component, finally we performed right upper lobectomy and R1 LN dissection. Postoperative histological examination showed that the tumor was entirely filled with mucin and there are a few tumor cells with the signet-ring shape in its marginal area. So, this tumor was diagnosed as mucinous cystic adenocarcinoma of the lung with signet ring cells. This type of the lung adenocarcinoma was rare case, but we need to have much attentions because of the clinical differences from the other type of adenocarcinoma.