Metachronous pubic bone metastases from synchronous double cancer with prostate and ascending colon cancers: A case report

A 70-year-old man visited a private hospital with the chief complaint of right lower limb pain. Fluorodeoxyglucose-emission tomography (FDG-PET) showed abnormal uptake in the pubic bone, right femur, and ascending colon. The patient was referred to our hospital for further evaluation. The following tumor marker levels were found: prostate-specific antigen (PSA) 20.57 ng/ml, carcinoembryonic antigen (CEA) 108.5 ng/ml, carbohydrate antigen 19-9 (CA19-9) 1,002.1 U/ml. An open pubic bone biopsy was performed. The pathological diagnosis was metastatic adenocarcinoma from prostate cancer. Prostate and ascending colon cancers were clinically diagnosed as T2bN0Mlb and T2N0M0, respectively. Laparoscopic colectomy was performed. Androgen deprivation therapy started immediately and the serum PSA level was maintained at <0.2 ng/ml during the follow-up period. However, the CEA and CA 19-9 were higher than the normal level 2 years after the surgery. In addition, the FDG-PET revealed abnormal uptake in the pubic bone. Thus, a pubic bone biopsy was performed again. The histological diagnosis was metastatic adenocarcinoma from the ascending colon cancer. Although the patient received combination chemotherapy, he died of colon cancer.