[Recrudescence of prostate cancer with low serum level of PSA and high serum level of CEA and CA19-9: a case report].

We report a case of primary adenocarcinoma of the prostate producing carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9). A 64-year-old man referred to our hospital with dysbasia. Two years ago, he was diagnosed with prostate cancer at another hospital and received radiotherapy and endocrine therapy. Serum CEA and CA 19-9 levels were increased to 3,990 ng/ml and 11,700 U/ml at the time of our hospitalization. However, his serum PSA level remained low. After hospitalization, the disease rapidly progressed and he died a month later. In the histology of autopsy specimen, the prostate showed no sign of malignancy, but bone showed metastasis of prostate cancer. Immunohistochemical staining for CEA and PSA demonstrated the existence of each protein in bone metastasis.