Ground-glass attenuation in nodular bronchioloalveolar carcinoma: CT patterns and prognostic value

Purpose: The purpose of our study was to assess the CT patterns and prognostic value of ground-glass attenuation in nodular bronchioloalveolar carcinoma (BAG). Method: We retrospectively reviewed CT examinations of 22 patients with 24 nodular BACs who underwent surgery. CT and pathologic findings were analyzed and correlated with postoperative course of disease. Results: We detected five patterns of ground-glass attenuation associated with nodular BAG: pure ground-glass nodule (n = 1), ground-glass nodule with superimposed lymphangitis (n = 1), nodule with mixed areas of ground-glass attenuation and consolidation (n = 2), ground-glass halo around nodule (halo sign) (n = 3), and nodule associated with a plurisegmental area of ground-glass attenuation (n = 1). Two patients with the halo sign and a third patient with a plurisegmental area of ground-glass attenuation rapidly developed diffuse pulmonary disease by bronchogenic spread and died a few months after surgery. Conclusion: Our series demonstrates that focal BAC may progress to diffuse pulmonary involvement by bronchogenic spread. The presence of a large area of ground-glass attenuation associated with a nodular BAC might be the CT sign of an aggressive biologic behavior. In these cases there is a high likelihood for diffuse disease to develop from bronchogenic spread.