Purpose: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Brain metastasis from osteosarcoma was once uncommon; however, with the advent of chemotherapeutic agents and improved imaging modalities, it has become a more common and recognized finding. Brain metastases are, rarely, the initial presenting symptom, but instead are a late and preterminal event in the disease process. When osteosarcomas manifest in the central nervous system, they tend to occur in the gray-white junction in the anterior circulation akin to other metastatic lesions in the brain.
Case report: The authors report a case of a 16-year-old boy who presented with acute neurological deterioration due to a posterior fossa hemorrhage and was subsequently found to have a primary site localizing to the metaphysis of the right femur with florid metastatic disease.
Conclusions: This is the first case reported in the literature in which an osteosarcoma initially presented as cerebral metastasis in the form of a posterior fossa hemorrhage with a rapidly deteriorating course.