[Experience with High-grade Fetal Lung Adenocarcinoma;Report of a Case].

A 61-year-old woman, who was revealed to have a 11 mm pulmonary nodule in the right middle lobe by computed tomography, was diagnosed with adenocarcinoma using bronchoscopy. Fluorodeoxyglucose-positron emission tomography (FDG-PET) showed FDG accumulation in the tumor, with a maximum standardized uptake value( SUVmax) of 2.47. Therefore, she underwent thoracoscopic right middle lobectomy. Histopathological examination revealed invasive growth of cylindrical tumor cells with clear glycogen-filled cytoplasm and a relatively high-grade nuclear atypia in tubulopapillary structures; no morula was observed. Immunohistochemically, the membranes of the tumor cells were positively stained for β-catenin, indicating high-grade fetal adenocarcinoma (pT1bN0M0, pathologic stageⅠA2). The postoperative course was uneventful, without recurrence 6 months after surgery.