[Osteosarcoma of the prostate after radiotherapy]

Osteosarcoma of the prostate is a rare finding. These tumours usually occur years after radiotherapy for prostate cancer. We report the case of a 74-year-old man with prostate cancer who had been treated with radiotherapy and androgen deprivation therapy. The man presented with urinary retention and his prostate was transurethrally resected. The histopathological investigation showed formations of a poorly differentiated osteosarcoma in the prostate. Because of serious comorbidities we decided to withhold chemotherapy considering its potential side effects. The man died a few months after the diagnosis of osteosarcoma in the prostate with the disease in a metastatic stage. In conclusion, osteosarcoma of the prostate is a rarely reported consequence of radiotherapy in patients with prostate cancer and is characterised by poor life expectancy.