Bronchioloalveolar carcinoma is a subtype of lung adenocarcinoma, characterized by well-differentiated cytology, peripheral location, and characteristic growth of neoplastic cells along intact alveolar septa (ie, lepidic growth pattern). Pure bronchioloalveolar carcinoma, by definition, doesn’t invade stroma, pleura, or lymphatic spaces. If there is lymphatic invasion, the tumor is classified a...