高悪性度型胎児型肺腺癌の1例

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

はじめに　胎児型腺癌は胎児肺に類似した成分により構成される腫瘍で，全肺癌の約0.1％1）と報告されているまれな腫瘍である．われわれは高悪性度型胎児型腺癌の1例を経験したので報告する．

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.