Radiotherapy-associated intra-abdominal angiosarcoma after prostatic adenocarcinoma: Case reports.

Angiosarcoma is a rare soft tissue neoplasm, which accounts for <1% of all soft tissue tumours. It has been previously reported that the incidence rate of angiosarcomas increases following radiotherapy. The present study reports two cases of intra-abdominal angiosarcoma associated with previous radiotherapy treatment. To the best of our knowledge, these associations have not been previously described in English literature. The patients aged 71 and 83 years were admitted to the center for abdominal pain and diarrhea. Each patient had previously had treatment with radiotherapy for prostate adenocarcinoma. During their hospitalization, biopsies were obtained and the diagnosis of angiosarcoma was reached. In each patient the tumors had irregular proliferating vascular channels, lined by atypical endothelial cells, which varied from elongated and spindle-shaped to large and plump. Immunocytochemistry revealed that the tumor cells were positive for the cytoplasmic endothelial markers cluster of differentiation (CD)31 and CD34. The recognition of these associations is important and their occurrence in this rare type of neoplasm should not mislead the pathologist and cause a misdiagnosis of the sarcoma.