The first case of micropapillary adenocarcinoma associated with cystic airspace in a non-smoking man.

Lung cancers associated with cystic airspaces are attracting increasing attention because of delayed diagnosis. The cancers that usually occur in smokers comprise lepidic, papillary, and/or acinar adenocarcinoma, but a micropapillary type has not been described to date. Pulmonary micropapillary adenocarcinoma was added to the 2015 World Health Organization (WHO) classification system as a new subtype with a notably poor prognosis. We describe the first micropapillary adenocarcinoma of the lung associated with cystic airspaces in a 79-year-old non-smoking man.