Well-differentiated fetal adenocarcinoma of the lung

We describe the case of a 43-year-old woman with a tumor shadow in the uppe r lobe of the left lung. The tumor was initially suspected to be a carcinoi d tumor, following percutaneous needle biopsy. Subsequently, a left upper l obectomy was performed, and a well-differentiated fetal adenocarcinoma was diagnosed histologically. Unlike the biphasic epithelial and stromal featur es of pulmonary. blastoma, it was composed solely of malignant glands of em bryonal appearance.