Benign bronchopulmonary tumors: Radiologic and pathologic findings

According to the new World Health Organization classification, benign bronchopulmonary tumors can be classified into epithelial tumors, mesenchymal tumors, and tumor-like conditions. Imaging findings of benign tumors of large airways are nonspecific and overlapping. Some benign pulmonary tumors show characteristic imaging findings. On CT, bronchioloalveolar adenomas appear as a small nodular area of ground-glass opacity. Metastasizing leiomyomas are seen as well-circumscribed solitary or multiple pulmonary nodules ranging in size from a few millimeters to several centimeters. Pulmonary hamartomas or lipomas are recognized specifically when fat deposits of CT number in the -80 HU to -120 HU range are identified. Enhancement of tumor with administration of contrast medium with or without foci of calcification may be seen in sclerosing hemangiomas and hemangiopericytomas. Awareness of the various imaging findings of these tumors can help narrow down the differential diagnosis on daily practice among the long lists of bronchopulmonary tumors.