Alveolar Diseases

Adenocarcinoma has surpassed squamous cell carcinoma as the leading histologic type, accounting for 30 % of all cases of lung cancer. The new 2015 WHO classification provided the basis for a multidisciplinary approach emphasizing the close correlation among radiologic and histopathologic pattern of lung adenocarcinoma. The term “bronchioloalveolar carcinoma” has been eliminated, introducing the concepts of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) and the use of descriptive predominant patterns in invasive adenocarcinomas (lepidic, acinar, papillary, solid, and micropapillary patterns). Invasive mucinous adenocarcinoma is the new definition for mucinous bronchioloalveolar carcinoma.