[Paget's disease mimicking metastatic prostate cancer on bone scan image : a case report].

A 61-year-old man was referred to our hospital complaining of elevated serum prostate-specific antigen (PSA) (5.1 ng/ml). Histopathologic diagnosis with trans-rectal prostate biopsy specimen was adenocarcinoma, Gleason score 4+5 = 9. Bone scintigraphy revealed an abnormal uptake on left coxal bone. The patient was diagnosed with prostate cancer with bone metastasis. He received androgen deprivation therapy for two years. Serum PSA decreased to an undetected level. However, the abnormal activity of left coxal bone lesion was not changed on bone scintigraphy. Coxal bone biopsy was performed. The bone lesion was histopathologically diagnosed as Paget's disease of bone.