title: Sharply demarcated thoracic mass in an asymptomatic boy.
mesh_terms: D000293:Adolescent; D003949:Diagnostic Techniques, Surgical; D004443:Echinococcosis / Q000175:diagnosis; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D010995:Pleural Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery; D011859:Radiography