[A case of pulmonary blastoma coexisting with well-differentiated adenocarcinoma]

A 66-year-old man came to our hospital because of hemoptysis and fever. Chest radiograph and CT scan showed a large circumscribed shadow in the posterior segment of the right upper lobe. Bronchoscopy revealed bronchial compression and stenosis. The histopathological specimen obtained by transbronchial biopsy showed total necrosis, but cytological examination of the bronchial lavage specimen showed class 5 adenocarcinoma. Right upper lobectomy was done, and regional lymph nodes were removed. The resected tumor was found to be a pulmonary blastoma by histopathological examination. The main tumor was composed of malignant epithelial and mesenchymal elements with rhabdoid differentiation and chondroid tissue, the former of which looked like fetal lung tissue. This case is interesting, because the fact that the adenocarcinoma and pulmonary blastoma were close together may be related to the histogenesis of pulmonary blastoma.