Complete Response of Advanced Invasive Mucinous Adenocarcinoma of the Lung with Gemcitabine and Pemetrexed

In 2011,mucinous bronchioloalveolar carcinoma was reclassified as invasive mucinous adenocarcinoma, mucinous adenocarcinoma in situ,and mucinous minimally invasive adenocarcinoma.A part of the invasive mucinous adenocarcinoma of the lung differentiates to gastric mucous cells, and we term this type of carcinoma gastric-like invasive mucinous adenocarcinoma.However,treatment approaches have not yet been established. An 84-year-old Japanese male visited our hospital because of multiple consolidations and ground-glass opacity on his chest computed tomography. Surgical biopsy of the right lung ground-glass opacity was performed,and it was diagnosed as gastric-like invasive mucinous adenocarcinoma by immunohistochemical analysis.Treatment with gemcitabine and pemetrexed was quite effective,and the radiologic response was complete. We suggest that it is meaningful to determine whether the diagnosis of gastric-like invasive mucinous adenocarcinoma is correct because this may indicate a favourable response to the anticancer drug gemcitabine.Shinshu Med J 64 : 79―83, 2016 (Received for publication July 23,2015;accepted in revised form December 16,2015)