[Prostate cancer diagnosed through the biopsy of the bone metastatic lesion; a case report]

An 80-year-old man visited our clinic with the chief complaint of asymptomatic macroscopic hematuria secondary to anticoagulant medicine. Although digital rectal examination was normal, a high serum prostate specific antigen (PSA) level (85.9 ng/ml) led us to perform sextant prostate biopsy, resulting in negative for cancer. Three months later, since the serum PSA increased to 169 ng/ml with high serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 levels. Twelve-core prostate biopsy was performed again, but the result was negative. Pelvic magnetic resonance imaging (MRI) showed a metastatic lesion on the right pubic bone, which was biopsied, and turned out to be poorly differentiated prostate cancer in histology. Maximum androgen blockade failed to control PSA. Finally he died of pneumonia 55 days after the bone biopsy. To our knowledge, there were only two case reports diagnosed as prostate cancer by biopsies of the metastatic lesions in Japanese literature, but none in the English literature. These findings suggest that high serum levels of CEA and CA19-9 in patients with prostate cancer are indications of hormone-refractory prostate cancer resulting in poor prognosis.