Small Bowel Metastasis of Osteosarcoma Presenting with Intussusception: A Case Report

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. The lung is the most frequent site of metastasis, whereas extrapulmonary metastases, including those to the gastrointestinal tract, are rare. We report a case of small bowel metastasis of osteosarcoma presenting with intussusception.

A 19-year-old man with osteosarcoma of the left femur and synchronous pulmonary metastases underwent wide resection of the primary lesion followed by multiple pulmonary resections and multimodal chemotherapy, achieving temporary remission. Three years after the initial diagnosis, he presented with persistent fatigue and intermittent abdominal pain. Laboratory evaluation revealed severe anemia. Contrast-enhanced CT demonstrated intussusception of the proximal jejunum caused by an intraluminal tumor. Conservative treatment was unsuccessful, and surgical intervention was performed. Laparoscopic exploration revealed jejunal intussusception with a tumor serving as the lead point, which was confirmed at mini-laparotomy. Partial resection of the small bowel was undertaken. Histopathological examination showed atypical tumor cells with chondroid differentiation and osteoid formation, consistent with metastatic osteosarcoma. The postoperative course was uneventful, and the patient remained alive at 4 months after surgery. A review of the literature identified only 11 reported cases of small bowel metastasis from osteosarcoma, most of which presented with intussusception and were associated with a poor prognosis.

Small bowel metastasis of osteosarcoma is extremely rare but should be considered in patients with a history of osteosarcoma presenting with intussusception. Surgical resection may provide symptomatic relief and plays an important role not only in definitive diagnosis but also in improving QOL.