Intracranial manifestation of osteosarcoma.

Involvement of the central nervous system in osteosarcoma is uncommon. These neoplasms are most often located at the metaphyses of tubular bones and rarely in flat bones of vertebra, ribs, pelvis, facial bones, or skull. Tumors of the latter bones may obviously spread into the cerebrum. Osteosarcomas primarily metastasize hematogenously to the lungs. Bone, lymph node, or brain metastases are mostly seen following or concomitantly with pulmonary metastatic disease. However, there are single cases of primary osteosarcoma of the brain parenchyma without bone association or tumor manifestation at other locations. Three illustrative cases highlight the diversity of the clinical presentation of cerebral osteosarcoma: a 22-year-old man with multiple brain metastases following late pulmonary relapse of an osteosarcoma of the tibia, a 31-year-old woman with an osteosarcoma of the left anterior cranial fossa arising from the skull base, and a 78-year-old man presenting with primary osteogenic sarcoma of the left frontal cerebral hemisphere. According to the current literature, 10-15% of all osteosarcoma patients experiencing relapse may beat risk for central nervous system metastases. To the authors' best knowledge, there are 11 cases of primary intracerebral or meningeal osteogenic sarcoma, including this case report, without any skeletal attachment.