[A case report of pulmonary blastoma--well differentiated fetal adenocarcinoma].

We report a pulmonary blastoma lacking sarcomatous features in 33-year-old woman. Abnormal shadow was detected in the right upper field in a routine chest X-ray film. The preoperative imaging films showed a 4 x 4 cm, well-circumscribed solid tumor in S3 of the right lung. The preoperative clinical diagnosis of primary lung cancer was considered. The operative findings showed that an elastic hard tumor, 5 cm in diameter, was localized in S3 of the right lung and partially contacted the middle lobe. Right upper and middle lobe resection was performed with lymph node dissection. The postoperative diagnosis was pulmonary blastoma, well differentiated fetal lung (= WDFA). It is considered that the degree of the malignancy of WDFA is lower and the prognosis of WDFA is better than conventional pulmonary blastoma (= biphasic blastoma). There are not available treatments except for surgical resection. It is suggested that it necessary to collect as many cases as possible, to make definite classifications and to examine the clinical course and prognosis of pulmonary blastoma.