Peritoneal metastasis in osteosarcoma: report of one case.

We describe a rare case of peritoneal metastasis in osteosarcoma. A 14-year-old boy was diagnosed with osteosarcoma of the femur. Although initial treatment with surgical resection and chemotherapy was successful, a large inoperable pulmonary metastasis was detected 27 months after diagnosis of the primary tumor. At 38 months, whilst still receiving salvage chemotherapy, malignant ascites with peritoneal metastasis was detected. The patient died two months later from disease progression. This is probably the 6th case and youngest patient with peritoneal metastasis of osteosarcoma reported in the literature. For early diagnosis, patients with a history of osteosarcoma having persistent abdominal symptoms or signs should be offered a CT scan of the abdomen, and examination of the ascitic fluid when present. With advances in treatments, unusual sites of metastasis may become more prevalent.