A case of pulmonary blastoma

Abstract

We report herein a case of pulmonary blastoma without sarcomatous features. A 47-year-old male was pointed out to have an abnormal shadow, 3 cm in diameter, in the upper right lobe. Preoperative cytological examination failed to detect malignant cells. Exploratory thoracotomy was done because clinical findings suggested malignancy. Fine needle aspiration of the lung tumor intraoperatively demonstrated plane cell clusters with high cellularity. The clusters also showed a glandular pattern with slightly disordered polarity. Clear rimming of cytoplasm was observed at the luminal surface. From these features, well-differentiated adenocarcinoma was suggested and lobectomy was done.
Histological examination revealed obvious glandular structures composed of monotonous high columnar epithelium with pseudostratified nuclei. Cytoplasm was characteristically clear and contained glycogen. Morules were occasionally seen. These findings were very similar to those of the fetal lung and pointed to a diagnosis of pulmonary blastoma. Although there was a tiny chondroid focus, no sarcomatous elements were identified. Therefore, this tumor was categorized as pulmonary blastoma without sarcomatous features.