Pulmonary mucinous cystadenoma: a rare benign tumor of the lung.

Pulmonary mucinous cystadenoma (PMCA) is rare, with few reported cases. This tumor is histologically characterized by a benign proliferation of mucin-producing epithelial cells and bulky mucin inside the tumor. We present the case of a 71-year-old woman with increasing mass shadow on chest radiography who underwent tumor resection by video-assisted thoracic surgery. The tumor was diagnosed histologically as PMCA.