Abstract
A 56-year-old man, whose serum carcinoembryonic antigen (CEA) level had been 7.3ng/ml (nomal <5.0) in 1990 and increased gradually to as high as 237.9ng/ml in 1997, was referred to our hospital to investigate the causative malignancy. Chest computed tomography (CT) revealed a small irregular opacity 1cm in diameter in the right S3, and pretracheal (#3) lymphadenopathy. Exploratory thoracotomy was performed and the diagnosis of lymph node metastasis of adenocarcinoma was obtained by frozen sectioning. Subsequently, right upper lobectomy and mediastinal lymph node dissection were performed (pT1N2M0). The serum CEA level, which once dropped to 6.5ng/ml postoperatively, began to increase again, but repeated whole body screening, including F-18 fluorodeoxyglucose-positoron emission tomography (FDG-PET), couldn't reveal any recurrence or distant metastasis. In 2004, the serum CEA level reached up to 874ng/ml, and finally FDG-PET detected a minute abnormal uptake at the right sacroiliac joint, which was diagnosed as bone metastasis. Here, we report a case of latent lung cancer with elevated serum CEA whose primary site and metastasis could not be confirmed for many years in spite of repeated whole body screening.
