Nontraumatic warfarin-related intrapulmonary hemorrhage presenting as a lung mass

BACKGROUND: Although bleeding events are the major concern when using oral anticoagulants, intrathoracic hemorrhages due to warfarin are rare. Most cases in the literature have been related to trauma and have manifested as a hemothorax. Here we report a case of a nontraumatic hemorrhage within a pre-existing pulmonary cyst that presented as a lung mass during warfarin therapy. CASE PRESENTATION: A 75-year-old asymptomatic woman presented with a 10-cm-diameter mass on chest radiography that was not evident 6 months prior. She had been taking warfarin for paroxysmal atrial fibrillation and a transient ischemic attack. There was no history of chest trauma, warfarin overdosing, or any suspected interactions with other drugs such as nonsteroidal anti-inflammatory drugs or antibiotics. The prothrombin time/international normalized ratio(PT-INR) was prolonged at 4.73 and her hemoglobin level was 8.7 g/dl. Chest computed tomography(CT)revealed an air-fluid mass adjacent to the right upper and middle lobes with a pleural effusion. A CT scan obtained 15 years prior revealed a cyst at the corresponding site and the mass was diagnosed as a warfarin-related hemorrhage within the pre-existing pulmonary cyst. We performed a surgical resection of the cyst to prevent any worsening hemorrhage and subsequent infection. The postoperative course was uneventful and the patient was discharged on the 3rd postoperative day. CONCLUSION: A warfarin-related thoracic hemorrhage, other than a hemothorax, could manifest as a pulmonary mass on radiography in patients with pre-existing pulmonary cysts. History taking especially of any anticoagulant medications and a precise assessment of the past images are crucial for a correct diagnosis. Once the intrapulmonary cystic hemorrhage becomes evident, prompt withdrawal with a reversal of warfarin and surgical resection are required to prevent a worsening hemorrhage and subsequent infection.