Pneumopericardium is a rare dis or der hav ing trau matic and non-trau matic causes. Pen e trat ing or blunt chest trauma and iat ro genic com pli ca tions as so ci ated with sur gery, en do scopic pro ce dures or pos i tive pres sure ven ti la tion are ma jor causes. Spon ta ne ous pneumopericardium caused by can cer in va sion is very rare. We pres ent a 46-year-old man with buccal can cer and cavitated lung me tas ta sis, in which pneumopericardium was found by chest X-ray. A chest CT scan showed mul ti ple cavitary le sions of both lungs with broncho-cav ity and cav ity-pericardium com mu ni ca tion which may be one of pos si ble mech a nisms of spontaneous pneumopericardium in this case.