Malignant Pulmonary Neoplasms Causing Airspace Consolidation: CT Findings

Purpose : To determine the CT findings of consolidative malignant neoplasms of the lung.Materials and Methods : Seventeen patients in whom pulmonary consolidation was seen on chest radiography were involved in this study. In all cases malignancy was subsequently proven; the neoplasms involved were bronchioloalveolar carcinoma (n = 9), malignant lymphoma (n = 4), mucoepidermoid tumor (n = 1), metastasis from colon cancer (n = 2), and metastasis from pancreatic mucinous adenocarcinoma (n =1). CT images were retrospectively analyzed in terms of enhancement pattern of the consolidation, morphologic appearance of an air-bronchogram, CT angiogram sign, pseudocavitation, and lymphadenopathy.Results :Visually assessed enhancement pattern of the consolidation showed lower attenuation than adjacent muscles in bronchioloalveolar carcinoma (8/9) and metastasis (1/3); isoattenuation in malignant lymphoma (3/4), mucoepidermoid carcinoma (1/1), and metastasis (1/3); and higher attenuation in bronchioloalveolar carcinoma (1/9), malignant lymphoma (1/4), and metastasis (1/3). Among the 15 of 17 patients for whom an airbronchogram was available, a stretching and squeezing pattern was seen in bronchioloalveolar carcinoma (4/9), malignant lymphoma (3/4), and metastasis (1/3). CT angiogram sign was identified in bronchioloalveolarcarcinoma (5/9), malignant lymphoma (2/4), and metastasis (3/3). Pseudocavitation was observed in two patients with bronchioloalveolar carcinoma, while lymphadenopathy was seen in bronchioloalveolar carcinoma (4/9), malignant lymphoma (3/4), and metastasis (1/3). Conglomerate and extrathoracic lymphadenopathy are commonly associated with malignant lymphoma.Conclusion :Malignant neoplasms which apper as consolidative lung lesions appear not only as bronchioloalveolar carcinoma, which is well known, but also in other forms. Although these lesions cannot be differentiated on the basis of air-bronchography and CT angiography, poor enhancement of consolidative lesion andpseudocavitation are characteristic findings of bronchioloalveolar carcinoma, and conglomerate or extrathoracic lymphadenopathy are also characteristic of malignant lymphoma.