Pulmonary blastoma that was first diagnosed as dedifferentiated chondrosarcoma using medical thoracoscopy: A case report.

Medical thoracoscopy is useful for the diagnosis of indeterminate pleural effusion; however, caution is needed when confirming rare malignancies, such as pulmonary blastoma. Although surgical resection is the treatment of choice, appropriate adjuvant chemotherapy to improve the prognosis may be necessary if there is pleural metastasis.