Abstract
We report a 76-year-old man who underwent surgery for a clear cell adenocarcinoma detected on a health checkup. Chest computed tomography (CT) revealed a tumor at the S3 of the left lung. Transbronchial lung biopsy did not lead to a definitive diagnosis, and partial resection of the left lung was performed. Because rapid pathological diagnosis using a frozen specimen suggested adenocarcinoma, superior lobectomy of the left lung and mediastinal lymph node dissection were performed. Systemic diagnostic imaging before and after surgery did not reveal any tumorous lesion in other organs, and the clinical findings suggested a primary tumor of the lung. Postoperative pathological investigation showed that clear cells comprised 90% or more of the lesion, with small foci of papillary structure. Immunohistochemically, the tumor was positive for keratin, EMA, thyroid transcription factor-1, and surfactant apoprotein A, and negative for HMB45, suggesting a primary clear cell adenocarcinoma of the lung. There has been no recurrence during the 22 months of postoperative follow-up.
