Solitary Capillary Hemangioma of the Lung

We report 2 cases of capillary hemangioma, each presenting as a solitary nodule in the peripheral lung. Both of the patients were asymptomatic with a small solitary nodule that had revealed by computed tomography. In both cases, the nodule was resected surgically under a clinical diagnosis of early lung cancer. Macroscopically, each lesion was ill defined and irregular in shape with a dark brown cut surface. Microscopically, the alveolar septa in both nodules were thickened by accumulations of numerous thin-walled capillary vessels, which characteristically extended along, or infiltrated, each septum. We diagnosed these lesions as "solitary capillary hemangioma" of the peripheral lung. Tumors or tumorlike lesions of capillary vessels in the lung are rare. Among them, pulmonary capillary hemangiomatosis (PCH) has been described as multiple nodules in the lung parenchyma or bronchovascular walls, comprised of infiltrating thin-walled capillary blood vessels. Moreover, PCH-like foci have been found in a retrospective study of autopsy cases. However, the presented cases should be differentiated from PCH in terms of their clinical setting such as history of hypertension or veno-occlusive disease and multiplicity of the lesion. This is a rare case series of solitary capillary hemangioma discovered incidentally during life, and the lesions were difficult to differentiate radiologically from early lung cancer. After the recent advances in imaging diagnosis for early detection of peripheral lung cancer, these lesions are important to bear in mind for differential diagnosis of bronchioloalveolar carcinoma.