A case of rapidly progressing pulmonary carcinosarcoma with a difficult antemortem diagnosis

Background. Pulmonary carcinosarcoma is an extremely rare malignant lung tumor that shows a poor prognosis. Case. The patient was a 77-year-old man. A lung tumor of 7 cm in diameter with coarse calcification was detected in the right lower lobe in a medical examination. Transbronchial lung biopsy was performed twice, but did not result in a definitive diagnosis. The patient was referred to our hospital for further examination. The tumor rapidly increased in size before bronchoscopy could be performed and the patient developed hemotho-rax and died of acute respiratory failure. Autopsy was performed and lung carcinosarcoma was diagnosed. There was only a 3-month interval between the medical examination and death. Conclusion. We presented a case of pulmonary carcinosarcoma that rapidly progressed during the examination period, resulting in the patients death due to acute respiratory failure. Patients presenting with lung tumors with coarse calcification should undergo immediate treatment because the tumor may reflect a component of sarcoma.