A Rare Cause of Bowel Obstruction: Peritoneal Metastases in Osteosarcoma at the Tibia in a Young Female Patient with Brain Metastasis. Case Report.

Osteosarcomas are the most frequent primary malignant bone tumors in children and adolescents. Like brain metastases in osteosarcomas, the bowel metastases are very rare. We present the case of a 23-year-old female patient, diagnosed and operated in 2008 of osteosarcoma at the tibia, for which she had sessions of neoadjuvant and adjuvant chemotherapy, but presented lungs metastases for which she underwent surgery in 2014. Then, in March 2015, she was diagnosed with an intracranial expansive process, an osteosarcoma metastasis, for which a total ablation of the tumor was performed during the early postoperatory period, being transferred to the General Surgery Clinic for abdominal pain, abdominal distention, vomiting, and lack of intestinal transit regarding faeces and intestinal gas. Both clinically and imagistically, the diagnosis was of bowel obstruction. This was the reason for performing surgery, thus discovering a bowel obstruction secondary to a metastasis of the terminal ileum and liver metastases that were confirmed as osteosarcoma metastases from an anatomopathological and immunohistochemical point of view. The bowel metastases and the osteosarcoma brain metastases are very rare entities and, their association, most often with young patients, is exceptional. However, bowel metastases must be taken into account as a possible cause of bowel obstruction in patients with osteosarcoma.